Tag 3.8.25

Built from https://develop.svn.wordpress.org/tags/3.8.25@42518 git-svn-id: http://core.svn.wordpress.org/tags/3.8.25@42347 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Bump the 3.8 branch to 3.8.25.
2018-01-16 23:50:07 +00:00 · 2018-01-16 21:47:26 +00:00 · 2018-01-16 08:15:30 +00:00 · 2018-01-16 06:59:26 +00:00 · 2017-11-29 19:05:14 +00:00 · 2017-11-29 16:47:13 +00:00
48 changed files with 5646 additions and 3849 deletions
--- a/license.txt
+++ b/license.txt
@@ -1,6 +1,6 @@
 WordPress - Web publishing software

-Copyright 2015 by the contributors
+Copyright 2017 by the contributors

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
--- a/readme.html
+++ b/readme.html
@@ -9,7 +9,6 @@
 <body>
 <h1 id="logo">
 	<a href="http://wordpress.org/"><img alt="WordPress" src="wp-admin/images/wordpress-logo.png" /></a>
-	<br /> Version 3.8.14
 </h1>
 <p style="text-align: center">Semantic Personal Publishing Platform</p>

--- a/wp-admin/about.php
+++ b/wp-admin/about.php
@@ -39,7 +39,50 @@ include( ABSPATH . 'wp-admin/admin-header.php' );
 </h2>

 <div class="changelog point-releases">
-	<h3><?php echo _n( 'Maintenance and Security Release', 'Maintenance and Security Releases', 14 ); ?></h3>
+	<h3><?php echo _n( 'Maintenance and Security Release', 'Maintenance and Security Releases', 25 ); ?></h3>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+			'<strong>Version %1$s</strong> addressed some security issues.', 1 ), '3.8.25' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.25' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+			'<strong>Version %1$s</strong> addressed some security issues.', 4 ), '3.8.24' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.24' ); ?>
+	</p>
+	<p><?php printf( __( '<strong>Version %s</strong> addressed one security issue.' ), '3.8.23' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.23' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+			'<strong>Version %1$s</strong> addressed some security issues.', 7 ), '3.8.22' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.22' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+			'<strong>Version %1$s</strong> addressed some security issues.', 5 ), '3.8.21' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.21' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed %2$s bug.',
+			'<strong>Version %1$s</strong> addressed %2$s bugs.', 1 ), '3.8.20', number_format_i18n( 1 ) ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.20' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+         '<strong>Version %1$s</strong> addressed some security issues.', 5 ), '3.8.19' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.19' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+         '<strong>Version %1$s</strong> addressed some security issues.', 3 ), '3.8.18' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.18' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+         '<strong>Version %1$s</strong> addressed some security issues.', 8 ), '3.8.17' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.17' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+         '<strong>Version %1$s</strong> addressed some security issues.', 2 ), '3.8.16' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.16' ); ?>
+	</p>
+	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
+         '<strong>Version %1$s</strong> addressed some security issues.', 9 ), '3.8.15' ); ?>
+		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.15' ); ?>
+	</p>
 	<p><?php printf( _n( '<strong>Version %1$s</strong> addressed a security issue.',
         '<strong>Version %1$s</strong> addressed some security issues.', 6 ), '3.8.14' ); ?>
 		<?php printf( __( 'For more information, see <a href="%s">the release notes</a>.' ), 'https://codex.wordpress.org/Version_3.8.14' ); ?>
--- a/wp-admin/customize.php
+++ b/wp-admin/customize.php
@@ -15,9 +15,10 @@ if ( ! current_user_can( 'edit_theme_options' ) )

 wp_reset_vars( array( 'url', 'return' ) );
 $url = urldecode( $url );
+$url = esc_url_raw( $url );
 $url = wp_validate_redirect( $url, home_url( '/' ) );
 if ( $return )
-	$return = wp_validate_redirect( urldecode( $return ) );
+	$return = wp_validate_redirect( esc_url_raw( urldecode( $return ) ) );
 if ( ! $return )
 	$return = $url;

--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -2222,7 +2222,7 @@ function wp_ajax_get_revision_diffs() {
 	if ( ! $post = get_post( (int) $_REQUEST['post_id'] ) )
 		wp_send_json_error();

-	if ( ! current_user_can( 'read_post', $post->ID ) )
+	if ( ! current_user_can( 'edit_post', $post->ID ) )
 		wp_send_json_error();

 	// Really just pre-loading the cache here.
--- a/wp-admin/includes/class-wp-plugins-list-table.php
+++ b/wp-admin/includes/class-wp-plugins-list-table.php
@@ -339,26 +339,26 @@ class WP_Plugins_List_Table extends WP_List_Table {
 			if ( $screen->in_admin( 'network' ) ) {
 				if ( $is_active ) {
 					if ( current_user_can( 'manage_network_plugins' ) )
-						$actions['deactivate'] = '<a href="' . wp_nonce_url('plugins.php?action=deactivate&amp;plugin=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'deactivate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Deactivate this plugin') . '">' . __('Network Deactivate') . '</a>';
+						$actions['deactivate'] = '<a href="' . wp_nonce_url('plugins.php?action=deactivate&amp;plugin=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'deactivate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Deactivate this plugin') . '">' . __('Network Deactivate') . '</a>';
 				} else {
 					if ( current_user_can( 'manage_network_plugins' ) )
-						$actions['activate'] = '<a href="' . wp_nonce_url('plugins.php?action=activate&amp;plugin=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'activate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Activate this plugin for all sites in this network') . '" class="edit">' . __('Network Activate') . '</a>';
+						$actions['activate'] = '<a href="' . wp_nonce_url('plugins.php?action=activate&amp;plugin=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'activate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Activate this plugin for all sites in this network') . '" class="edit">' . __('Network Activate') . '</a>';
 					if ( current_user_can( 'delete_plugins' ) && ! is_plugin_active( $plugin_file ) )
-						$actions['delete'] = '<a href="' . wp_nonce_url('plugins.php?action=delete-selected&amp;checked[]=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'bulk-plugins') . '" title="' . esc_attr__('Delete this plugin') . '" class="delete">' . __('Delete') . '</a>';
+						$actions['delete'] = '<a href="' . wp_nonce_url('plugins.php?action=delete-selected&amp;checked[]=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'bulk-plugins') . '" title="' . esc_attr__('Delete this plugin') . '" class="delete">' . __('Delete') . '</a>';
 				}
 			} else {
 				if ( $is_active ) {
-					$actions['deactivate'] = '<a href="' . wp_nonce_url('plugins.php?action=deactivate&amp;plugin=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'deactivate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Deactivate this plugin') . '">' . __('Deactivate') . '</a>';
+					$actions['deactivate'] = '<a href="' . wp_nonce_url('plugins.php?action=deactivate&amp;plugin=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'deactivate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Deactivate this plugin') . '">' . __('Deactivate') . '</a>';
 				} else {
-					$actions['activate'] = '<a href="' . wp_nonce_url('plugins.php?action=activate&amp;plugin=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'activate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Activate this plugin') . '" class="edit">' . __('Activate') . '</a>';
+					$actions['activate'] = '<a href="' . wp_nonce_url('plugins.php?action=activate&amp;plugin=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'activate-plugin_' . $plugin_file) . '" title="' . esc_attr__('Activate this plugin') . '" class="edit">' . __('Activate') . '</a>';

 					if ( ! is_multisite() && current_user_can('delete_plugins') )
-						$actions['delete'] = '<a href="' . wp_nonce_url('plugins.php?action=delete-selected&amp;checked[]=' . $plugin_file . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'bulk-plugins') . '" title="' . esc_attr__('Delete this plugin') . '" class="delete">' . __('Delete') . '</a>';
+						$actions['delete'] = '<a href="' . wp_nonce_url('plugins.php?action=delete-selected&amp;checked[]=' . urlencode( $plugin_file ) . '&amp;plugin_status=' . $context . '&amp;paged=' . $page . '&amp;s=' . $s, 'bulk-plugins') . '" title="' . esc_attr__('Delete this plugin') . '" class="delete">' . __('Delete') . '</a>';
 				} // end if $is_active
 			 } // end if $screen->in_admin( 'network' )

 			if ( ( ! is_multisite() || $screen->in_admin( 'network' ) ) && current_user_can('edit_plugins') && is_writable(WP_PLUGIN_DIR . '/' . $plugin_file) )
-				$actions['edit'] = '<a href="plugin-editor.php?file=' . $plugin_file . '" title="' . esc_attr__('Open this file in the Plugin Editor') . '" class="edit">' . __('Edit') . '</a>';
+				$actions['edit'] = '<a href="plugin-editor.php?file=' . urlencode( $plugin_file ) . '" title="' . esc_attr__('Open this file in the Plugin Editor') . '" class="edit">' . __('Edit') . '</a>';
 		} // end if $context

 		$prefix = $screen->in_admin( 'network' ) ? 'network_admin_' : '';
--- a/wp-admin/includes/class-wp-posts-list-table.php
+++ b/wp-admin/includes/class-wp-posts-list-table.php
@@ -587,8 +587,9 @@ class WP_Posts_List_Table extends WP_List_Table {
 					echo '<div class="locked-info"><span class="locked-avatar">' . $locked_avatar . '</span> <span class="locked-text">' . $locked_text . "</span></div>\n";
 				}

-				if ( ! $this->hierarchical_display && 'excerpt' == $mode && current_user_can( 'read_post', $post->ID ) )
-						the_excerpt();
+				if ( ! $this->hierarchical_display && 'excerpt' == $mode && current_user_can( 'read_post', $post->ID ) ) {
+						echo esc_html( get_the_excerpt() );
+				}

 				$actions = array();
 				if ( $can_edit_post && 'trash' != $post->post_status ) {
--- a/wp-admin/includes/class-wp-upgrader.php
+++ b/wp-admin/includes/class-wp-upgrader.php
@@ -1601,8 +1601,12 @@ class File_Upload_Upgrader {
 			if ( ! ( ( $uploads = wp_upload_dir() ) && false === $uploads['error'] ) )
 				wp_die( $uploads['error'] );

-			$this->filename = $_GET[$urlholder];
+			$this->filename = sanitize_file_name( $_GET[ $urlholder ] );
 			$this->package = $uploads['basedir'] . '/' . $this->filename;
+
+			if ( 0 !== strpos( realpath( $this->package ), realpath( $uploads['basedir'] ) ) ) {
+				wp_die( __( 'Please select a file' ) );
+			}
 		}
 	}

--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -609,6 +609,10 @@ function _unzip_file_ziparchive($file, $to, $needed_dirs = array() ) {
 		if ( '__MACOSX/' === substr($info['name'], 0, 9) ) // Skip the OS X-created __MACOSX directory
 			continue;

+		if ( 0 !== validate_file( $info['name'] ) ) {
+			return new WP_Error( 'invalid_file_ziparchive', __( 'Could not extract file from archive.' ), $info['name'] );
+		}
+
 		$uncompressed_size += $info['size'];

 		if ( '/' == substr($info['name'], -1) ) // directory
@@ -762,6 +766,10 @@ function _unzip_file_pclzip($file, $to, $needed_dirs = array()) {
 		if ( '__MACOSX/' === substr($file['filename'], 0, 9) ) // Don't extract the OS X-created __MACOSX directory files
 			continue;

+		if ( 0 !== validate_file( $file['filename'] ) ) {
+			return new WP_Error( 'invalid_file_pclzip', __( 'Could not extract file from archive.' ), $file['filename'] );
+		}
+
 		if ( ! $wp_filesystem->put_contents( $to . $file['filename'], $file['content'], FS_CHMOD_FILE) )
 			return new WP_Error( 'copy_failed_pclzip', __( 'Could not copy file.' ), $file['filename'] );
 	}
@@ -950,14 +958,28 @@ function request_filesystem_credentials($form_post, $type = '', $error = false,

 	$credentials = get_option('ftp_credentials', array( 'hostname' => '', 'username' => ''));

+	$submitted_form = wp_unslash( $_POST );
+
+	// Verify nonce, or unset submitted form field values on failure
+	if ( ! isset( $_POST['_fs_nonce'] ) || ! wp_verify_nonce( $_POST['_fs_nonce'], 'filesystem-credentials' ) ) {
+		unset(
+			$submitted_form['hostname'],
+			$submitted_form['username'],
+			$submitted_form['password'],
+			$submitted_form['public_key'],
+			$submitted_form['private_key'],
+			$submitted_form['connection_type']
+		);
+	}
+
 	// If defined, set it to that, Else, If POST'd, set it to that, If not, Set it to whatever it previously was(saved details in option)
-	$credentials['hostname'] = defined('FTP_HOST') ? FTP_HOST : (!empty($_POST['hostname']) ? wp_unslash( $_POST['hostname'] ) : $credentials['hostname']);
-	$credentials['username'] = defined('FTP_USER') ? FTP_USER : (!empty($_POST['username']) ? wp_unslash( $_POST['username'] ) : $credentials['username']);
-	$credentials['password'] = defined('FTP_PASS') ? FTP_PASS : (!empty($_POST['password']) ? wp_unslash( $_POST['password'] ) : '');
+	$credentials['hostname'] = defined('FTP_HOST') ? FTP_HOST : (!empty($submitted_form['hostname']) ? $submitted_form['hostname'] : $credentials['hostname']);
+	$credentials['username'] = defined('FTP_USER') ? FTP_USER : (!empty($submitted_form['username']) ? $submitted_form['username'] : $credentials['username']);
+	$credentials['password'] = defined('FTP_PASS') ? FTP_PASS : (!empty($submitted_form['password']) ? $submitted_form['password'] : '');

 	// Check to see if we are setting the public/private keys for ssh
-	$credentials['public_key'] = defined('FTP_PUBKEY') ? FTP_PUBKEY : (!empty($_POST['public_key']) ? wp_unslash( $_POST['public_key'] ) : '');
-	$credentials['private_key'] = defined('FTP_PRIKEY') ? FTP_PRIKEY : (!empty($_POST['private_key']) ? wp_unslash( $_POST['private_key'] ) : '');
+	$credentials['public_key'] = defined('FTP_PUBKEY') ? FTP_PUBKEY : (!empty($submitted_form['public_key']) ? $submitted_form['public_key'] : '');
+	$credentials['private_key'] = defined('FTP_PRIKEY') ? FTP_PRIKEY : (!empty($submitted_form['private_key']) ? $submitted_form['private_key'] : '');

 	//sanitize the hostname, Some people might pass in odd-data:
 	$credentials['hostname'] = preg_replace('|\w+://|', '', $credentials['hostname']); //Strip any schemes off
@@ -974,8 +996,8 @@ function request_filesystem_credentials($form_post, $type = '', $error = false,
 		$credentials['connection_type'] = 'ssh';
 	else if ( (defined('FTP_SSL') && FTP_SSL) && 'ftpext' == $type ) //Only the FTP Extension understands SSL
 		$credentials['connection_type'] = 'ftps';
-	else if ( !empty($_POST['connection_type']) )
-		$credentials['connection_type'] = wp_unslash( $_POST['connection_type'] );
+	else if ( !empty($submitted_form['connection_type']) )
+		$credentials['connection_type'] = $submitted_form['connection_type'];
 	else if ( !isset($credentials['connection_type']) ) //All else fails (And it's not defaulted to something else saved), Default to FTP
 		$credentials['connection_type'] = 'ftp';

@@ -1099,11 +1121,14 @@ jQuery(function($){

 <?php
 foreach ( (array) $extra_fields as $field ) {
-	if ( isset( $_POST[ $field ] ) )
-		echo '<input type="hidden" name="' . esc_attr( $field ) . '" value="' . esc_attr( wp_unslash( $_POST[ $field ] ) ) . '" />';
+	if ( isset( $submitted_form[ $field ] ) )
+		echo '<input type="hidden" name="' . esc_attr( $field ) . '" value="' . esc_attr( $submitted_form[ $field ] ) . '" />';
 }
-submit_button( __( 'Proceed' ), 'button', 'upgrade' );
 ?>
+	<p class="request-filesystem-credentials-action-buttons">
+		<?php wp_nonce_field( 'filesystem-credentials', '_fs_nonce', false, true ); ?>
+		<?php submit_button( __( 'Proceed' ), 'button', 'upgrade', false ); ?>
+	</p>
 </div>
 </form>
 <?php
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -221,7 +221,7 @@ function media_handle_upload($file_id, $post_id, $post_data = array(), $override
 	$url = $file['url'];
 	$type = $file['type'];
 	$file = $file['file'];
-	$title = $name;
+	$title = sanitize_text_field( $name );
 	$content = '';

 	if ( preg_match( '#^audio#', $type ) ) {
@@ -2581,7 +2581,7 @@ function wp_add_id3_tag_data( &$metadata, $data ) {
 		if ( ! empty( $data[$version]['comments'] ) ) {
 			foreach ( $data[$version]['comments'] as $key => $list ) {
 				if ( ! empty( $list ) ) {
-					$metadata[$key] = reset( $list );
+					$metadata[$key] = wp_kses_post( reset( $list ) );
 					// fix bug in byte stream analysis
 					if ( 'terms_of_use' === $key && 0 === strpos( $metadata[$key], 'yright notice.' ) )
 						$metadata[$key] = 'Cop' . $metadata[$key];
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -154,6 +154,13 @@ function _wp_translate_postdata( $update = false, $post_data = null ) {
 		$post_data['post_date_gmt'] = get_gmt_from_date( $post_data['post_date'] );
 	}

+	if ( isset( $post_data['post_category'] ) ) {
+		$category_object = get_taxonomy( 'category' );
+		if ( ! current_user_can( $category_object->cap->assign_terms ) ) {
+			unset( $post_data['post_category'] );
+		}
+	}
+
 	return $post_data;
 }

@@ -1147,11 +1154,11 @@ function get_sample_permalink_html( $id, $new_title = null, $new_slug = null ) {
 	}

 	if ( false === strpos($permalink, '%postname%') && false === strpos($permalink, '%pagename%') ) {
-		$return = '<strong>' . __('Permalink:') . "</strong>\n" . '<span id="sample-permalink" tabindex="-1">' . $permalink . "</span>\n";
+		$return = '<strong>' . __('Permalink:') . "</strong>\n" . '<span id="sample-permalink" tabindex="-1">' . esc_html( $permalink ) . "</span>\n";
 		if ( '' == get_option( 'permalink_structure' ) && current_user_can( 'manage_options' ) && !( 'page' == get_option('show_on_front') && $id == get_option('page_on_front') ) )
 			$return .= '<span id="change-permalinks"><a href="options-permalink.php" class="button button-small" target="_blank">' . __('Change Permalinks') . "</a></span>\n";
 		if ( isset( $view_post ) )
-			$return .= "<span id='view-post-btn'><a href='$permalink' class='button button-small'>$view_post</a></span>\n";
+			$return .= "<span id='view-post-btn'><a href='" . esc_url( $permalink ) . "' class='button button-small'>$view_post</a></span>\n";

 		$return = apply_filters('get_sample_permalink_html', $return, $id, $new_title, $new_slug);

@@ -1172,16 +1179,16 @@ function get_sample_permalink_html( $id, $new_title = null, $new_slug = null ) {
 		}
 	}

-	$post_name_html = '<span id="editable-post-name" title="' . $title . '">' . $post_name_abridged . '</span>';
-	$display_link = str_replace(array('%pagename%','%postname%'), $post_name_html, $permalink);
+	$post_name_html = '<span id="editable-post-name" title="' . $title . '">' . esc_html( $post_name_abridged ) . '</span>';
+	$display_link = str_replace(array('%pagename%','%postname%'), $post_name_html, esc_html( $permalink ) );
 	$view_link = str_replace(array('%pagename%','%postname%'), $post_name, $permalink);
 	$return =  '<strong>' . __('Permalink:') . "</strong>\n";
 	$return .= '<span id="sample-permalink" tabindex="-1">' . $display_link . "</span>\n";
 	$return .= '&lrm;'; // Fix bi-directional text display defect in RTL languages.
 	$return .= '<span id="edit-slug-buttons"><a href="#post_name" class="edit-slug button button-small hide-if-no-js" onclick="editPermalink(' . $id . '); return false;">' . __('Edit') . "</a></span>\n";
-	$return .= '<span id="editable-post-name-full">' . $post_name . "</span>\n";
+	$return .= '<span id="editable-post-name-full">' . esc_html( $post_name ) . "</span>\n";
 	if ( isset($view_post) )
-		$return .= "<span id='view-post-btn'><a href='$view_link' class='button button-small'>$view_post</a></span>\n";
+		$return .= "<span id='view-post-btn'><a href='" . esc_url( $view_link ) . "' class='button button-small'>$view_post</a></span>\n";

 	$return = apply_filters('get_sample_permalink_html', $return, $id, $new_title, $new_slug);

--- a/wp-admin/includes/screen.php
+++ b/wp-admin/includes/screen.php
@@ -885,7 +885,8 @@ final class WP_Screen {

 		switch ( $this->id ) {
 			case 'widgets':
-				$this->_screen_settings = '<p><a id="access-on" href="widgets.php?widgets-access=on">' . __('Enable accessibility mode') . '</a><a id="access-off" href="widgets.php?widgets-access=off">' . __('Disable accessibility mode') . "</a></p>\n";
+				$nonce = wp_create_nonce( 'widgets-access' );
+				$this->_screen_settings = '<p><a id="access-on" href="widgets.php?widgets-access=on&_wpnonce=' . urlencode( $nonce ) . '">' . __('Enable accessibility mode') . '</a><a id="access-off" href="widgets.php?widgets-access=off&_wpnonce=' . urlencode( $nonce ) . '">' . __('Disable accessibility mode') . "</a></p>\n";
 				break;
 			default:
 				$this->_screen_settings = '';
--- a/wp-admin/includes/template.php
+++ b/wp-admin/includes/template.php
@@ -706,7 +706,7 @@ function page_template_dropdown( $default = '' ) {
 			$selected = " selected='selected'";
 		else
 			$selected = '';
-	echo "\n\t<option value='".$templates[$template]."' $selected>$template</option>";
+	echo "\n\t<option value='" . esc_attr( $templates[$template] ) ."' $selected>" . esc_html( $template ) . "</option>";
 	endforeach;
 }

--- a/wp-admin/includes/update-core.php
+++ b/wp-admin/includes/update-core.php
@@ -603,6 +603,9 @@ $_old_files = array(
 'wp-admin/images/stars-rtl.png',
 'wp-admin/images/wp-logo-vs-2x.png',
 'wp-admin/images/about-updates-2x.png',
+// 4.9.2
+'wp-includes/js/mediaelement/flashmediaelement.swf',
+'wp-includes/js/mediaelement/silverlightmediaelement.xap',
 );

 /**
@@ -920,7 +923,11 @@ function update_core($from, $to) {
 		$old_file = $to . $old_file;
 		if ( !$wp_filesystem->exists($old_file) )
 			continue;
-		$wp_filesystem->delete($old_file, true);
+
+		// If the file isn't deleted, try writing an empty string to the file instead.
+		if ( ! $wp_filesystem->delete( $old_file, true ) && $wp_filesystem->is_file( $old_file ) ) {
+			$wp_filesystem->put_contents( $old_file, '' );
+		}
 	}

 	// Remove any Genericons example.html's from the filesystem
--- a/wp-admin/js/customize-controls.js
+++ b/wp-admin/js/customize-controls.js
@@ -772,6 +772,16 @@
 			}
 		});

+		// Ensure preview nonce is included with every customized request, to allow post data to be read.
+		$.ajaxPrefilter( function injectPreviewNonce( options ) {
+			if ( ! /wp_customize=on/.test( options.data ) ) {
+				return;
+			}
+			options.data += '&' + $.param({
+				customize_preview_nonce: api.settings.nonce.preview
+			});
+		});
+
 		// Refresh the nonces if the preview sends updated nonces over.
 		previewer.bind( 'nonce', function( nonce ) {
 			$.extend( this.nonce, nonce );
--- a/wp-admin/js/customize-controls.min.js
+++ b/wp-admin/js/customize-controls.min.js
--- a/wp-admin/plugin-editor.php
+++ b/wp-admin/plugin-editor.php
@@ -86,9 +86,9 @@ default:
 			wp_die( $error );

 		if ( ( ! empty( $_GET['networkwide'] ) && ! is_plugin_active_for_network($file) ) || ! is_plugin_active($file) )
-			activate_plugin($file, "plugin-editor.php?file=$file&phperror=1", ! empty( $_GET['networkwide'] ) ); // we'll override this later if the plugin can be included without fatal error
+			activate_plugin($file, "plugin-editor.php?file=" . urlencode( $file ) . "&phperror=1", ! empty( $_GET['networkwide'] ) ); // we'll override this later if the plugin can be included without fatal error

-		wp_redirect( self_admin_url("plugin-editor.php?file=$file&a=te&scrollto=$scrollto") );
+		wp_redirect( self_admin_url("plugin-editor.php?file=" . urlencode( $file ) . "&a=te&scrollto=$scrollto") );
 		exit;
 	}

@@ -174,14 +174,14 @@ default:
 <big><?php
 	if ( is_plugin_active($plugin) ) {
 		if ( is_writeable($real_file) )
-			echo sprintf(__('Editing <strong>%s</strong> (active)'), $file);
+			echo sprintf(__('Editing <strong>%s</strong> (active)'), esc_html( $file ) );
 		else
-			echo sprintf(__('Browsing <strong>%s</strong> (active)'), $file);
+			echo sprintf(__('Browsing <strong>%s</strong> (active)'), esc_html( $file ) );
 	} else {
 		if ( is_writeable($real_file) )
-			echo sprintf(__('Editing <strong>%s</strong> (inactive)'), $file);
+			echo sprintf(__('Editing <strong>%s</strong> (inactive)'), esc_html( $file ) );
 		else
-			echo sprintf(__('Browsing <strong>%s</strong> (inactive)'), $file);
+			echo sprintf(__('Browsing <strong>%s</strong> (inactive)'), esc_html( $file ) );
 	}
 	?></big>
 </div>
@@ -225,7 +225,7 @@ foreach ( $plugin_files as $plugin_file ) :
 		continue;
 	}
 ?>
-		<li<?php echo $file == $plugin_file ? ' class="highlight"' : ''; ?>><a href="plugin-editor.php?file=<?php echo urlencode( $plugin_file ) ?>&amp;plugin=<?php echo urlencode( $plugin ) ?>"><?php echo $plugin_file ?></a></li>
+		<li<?php echo $file == $plugin_file ? ' class="highlight"' : ''; ?>><a href="plugin-editor.php?file=<?php echo urlencode( $plugin_file ) ?>&amp;plugin=<?php echo urlencode( $plugin ) ?>"><?php echo esc_html( $plugin_file ); ?></a></li>
 <?php endforeach; ?>
 	</ul>
 </div>
--- a/wp-admin/plugins.php
+++ b/wp-admin/plugins.php
@@ -17,7 +17,7 @@ $pagenum = $wp_list_table->get_pagenum();

 $action = $wp_list_table->current_action();

-$plugin = isset($_REQUEST['plugin']) ? $_REQUEST['plugin'] : '';
+$plugin = isset($_REQUEST['plugin']) ? wp_unslash( $_REQUEST['plugin'] ) : '';
 $s = isset($_REQUEST['s']) ? urlencode($_REQUEST['s']) : '';

 // Clean up request URI from temporary args for screen options/paging uri's to work as expected.
@@ -37,10 +37,10 @@ if ( $action ) {

 			check_admin_referer('activate-plugin_' . $plugin);

-			$result = activate_plugin($plugin, self_admin_url('plugins.php?error=true&plugin=' . $plugin), is_network_admin() );
+			$result = activate_plugin($plugin, self_admin_url('plugins.php?error=true&plugin=' . urlencode( $plugin ) ), is_network_admin() );
 			if ( is_wp_error( $result ) ) {
 				if ( 'unexpected_output' == $result->get_error_code() ) {
-					$redirect = self_admin_url('plugins.php?error=true&charsout=' . strlen($result->get_error_data()) . '&plugin=' . $plugin . "&plugin_status=$status&paged=$page&s=$s");
+					$redirect = self_admin_url('plugins.php?error=true&charsout=' . strlen($result->get_error_data()) . '&plugin=' . urlencode( $plugin ) . "&plugin_status=$status&paged=$page&s=$s");
 					wp_redirect(add_query_arg('_error_nonce', wp_create_nonce('plugin-activation-error_' . $plugin), $redirect));
 					exit;
 				} else {
@@ -67,7 +67,7 @@ if ( $action ) {

 			check_admin_referer('bulk-plugins');

-			$plugins = isset( $_POST['checked'] ) ? (array) $_POST['checked'] : array();
+			$plugins = isset( $_POST['checked'] ) ? (array) wp_unslash( $_POST['checked'] ) : array();

 			// Only activate plugins which are not already active.
 			if ( is_network_admin() ) {
@@ -104,9 +104,9 @@ if ( $action ) {
 			check_admin_referer( 'bulk-plugins' );

 			if ( isset( $_GET['plugins'] ) )
-				$plugins = explode( ',', $_GET['plugins'] );
+				$plugins = explode( ',', wp_unslash( $_GET['plugins'] ) );
 			elseif ( isset( $_POST['checked'] ) )
-				$plugins = (array) $_POST['checked'];
+				$plugins = (array) wp_unslash( $_POST['checked'] );
 			else
 				$plugins = array();

@@ -176,7 +176,7 @@ if ( $action ) {

 			check_admin_referer('bulk-plugins');

-			$plugins = isset( $_POST['checked'] ) ? (array) $_POST['checked'] : array();
+			$plugins = isset( $_POST['checked'] ) ? (array) wp_unslash( $_POST['checked'] ) : array();
 			// Do not deactivate plugins which are already deactivated.
 			if ( is_network_admin() ) {
 				$plugins = array_filter( $plugins, 'is_plugin_active_for_network' );
@@ -208,7 +208,7 @@ if ( $action ) {
 			check_admin_referer('bulk-plugins');

 			//$_POST = from the plugin form; $_GET = from the FTP details screen.
-			$plugins = isset( $_REQUEST['checked'] ) ? (array) $_REQUEST['checked'] : array();
+			$plugins = isset( $_REQUEST['checked'] ) ? (array) wp_unslash( $_REQUEST['checked'] ) : array();
 			if ( empty( $plugins ) ) {
 				wp_redirect( self_admin_url("plugins.php?plugin_status=$status&paged=$page&s=$s") );
 				exit;
@@ -220,6 +220,14 @@ if ( $action ) {
 				exit;
 			}

+			// Bail on all if any paths are invalid.
+			// validate_file() returns truthy for invalid files
+			$invalid_plugin_files = array_filter( $plugins, 'validate_file' );
+			if ( $invalid_plugin_files ) {
+				wp_redirect( self_admin_url("plugins.php?plugin_status=$status&paged=$page&s=$s") );
+				exit;
+			}
+
 			include(ABSPATH . 'wp-admin/update.php');

 			$parent_file = 'plugins.php';
--- a/wp-admin/press-this.php
+++ b/wp-admin/press-this.php
@@ -34,8 +34,25 @@ function press_it() {
 	if ( !current_user_can('edit_post', $post_ID) )
 		wp_die(__('You are not allowed to edit this post.'));

-	$post['post_category'] = isset($_POST['post_category']) ? $_POST['post_category'] : '';
-	$post['tax_input'] = isset($_POST['tax_input']) ? $_POST['tax_input'] : '';
+	// Only accept categories if the user actually can assign
+	$category_tax = get_taxonomy( 'category' );
+	if ( current_user_can( $category_tax->cap->assign_terms ) ) {
+		$post['post_category'] = ( ! empty( $_POST['post_category'] ) ) ? $_POST['post_category'] : array();
+	}
+
+	// Only accept taxonomies if the user can actually assign
+	if ( ! empty( $_POST['tax_input'] ) ) {
+		$tax_input = $_POST['tax_input'];
+		foreach ( $tax_input as $tax => $_ti ) {
+			$tax_object = get_taxonomy( $tax );
+			if ( ! $tax_object || ! current_user_can( $tax_object->cap->assign_terms ) ) {
+				unset( $tax_input[ $tax ] );
+			}
+		}
+
+		$post['tax_input'] = $tax_input;
+	}
+
 	$post['post_title'] = isset($_POST['title']) ? $_POST['title'] : '';
 	$content = isset($_POST['content']) ? $_POST['content'] : '';

@@ -509,75 +526,81 @@ $admin_body_class .= ' locale-' . sanitize_html_class( strtolower( str_replace(
 				</div>
 			</div>

-			<?php $tax = get_taxonomy( 'category' ); ?>
-			<div id="categorydiv" class="postbox">
-				<div class="handlediv" title="<?php esc_attr_e( 'Click to toggle' ); ?>"><br /></div>
-				<h3 class="hndle"><?php _e('Categories') ?></h3>
-				<div class="inside">
-				<div id="taxonomy-category" class="categorydiv">
+			<?php

-					<ul id="category-tabs" class="category-tabs">
-						<li class="tabs"><a href="#category-all"><?php echo $tax->labels->all_items; ?></a></li>
-						<li class="hide-if-no-js"><a href="#category-pop"><?php _e( 'Most Used' ); ?></a></li>
-					</ul>
+			$tax = get_taxonomy( 'category' );
+			if ( current_user_can( $tax->cap->assign_terms ) ) :
+				?>
+				<div id="categorydiv" class="postbox">
+					<div class="handlediv" title="<?php esc_attr_e( 'Click to toggle' ); ?>"><br /></div>
+					<h3 class="hndle"><?php _e('Categories') ?></h3>
+					<div class="inside">
+					<div id="taxonomy-category" class="categorydiv">

-					<div id="category-pop" class="tabs-panel" style="display: none;">
-						<ul id="categorychecklist-pop" class="categorychecklist form-no-clear" >
-							<?php $popular_ids = wp_popular_terms_checklist( 'category' ); ?>
+						<ul id="category-tabs" class="category-tabs">
+							<li class="tabs"><a href="#category-all"><?php echo $tax->labels->all_items; ?></a></li>
+							<li class="hide-if-no-js"><a href="#category-pop"><?php _e( 'Most Used' ); ?></a></li>
 						</ul>
-					</div>

-					<div id="category-all" class="tabs-panel">
-						<ul id="categorychecklist" data-wp-lists="list:category" class="categorychecklist form-no-clear">
-							<?php wp_terms_checklist($post_ID, array( 'taxonomy' => 'category', 'popular_cats' => $popular_ids ) ) ?>
-						</ul>
-					</div>
-
-					<?php if ( !current_user_can($tax->cap->assign_terms) ) : ?>
-					<p><em><?php _e('You cannot modify this Taxonomy.'); ?></em></p>
-					<?php endif; ?>
-					<?php if ( current_user_can($tax->cap->edit_terms) ) : ?>
-						<div id="category-adder" class="wp-hidden-children">
-							<h4>
-								<a id="category-add-toggle" href="#category-add" class="hide-if-no-js">
-									<?php printf( __( '+ %s' ), $tax->labels->add_new_item ); ?>
-								</a>
-							</h4>
-							<p id="category-add" class="category-add wp-hidden-child">
-								<label class="screen-reader-text" for="newcategory"><?php echo $tax->labels->add_new_item; ?></label>
-								<input type="text" name="newcategory" id="newcategory" class="form-required form-input-tip" value="<?php echo esc_attr( $tax->labels->new_item_name ); ?>" aria-required="true"/>
-								<label class="screen-reader-text" for="newcategory_parent">
-									<?php echo $tax->labels->parent_item_colon; ?>
-								</label>
-								<?php wp_dropdown_categories( array( 'taxonomy' => 'category', 'hide_empty' => 0, 'name' => 'newcategory_parent', 'orderby' => 'name', 'hierarchical' => 1, 'show_option_none' => '&mdash; ' . $tax->labels->parent_item . ' &mdash;' ) ); ?>
-								<input type="button" id="category-add-submit" data-wp-lists="add:categorychecklist:category-add" class="button category-add-submit" value="<?php echo esc_attr( $tax->labels->add_new_item ); ?>" />
-								<?php wp_nonce_field( 'add-category', '_ajax_nonce-add-category', false ); ?>
-								<span id="category-ajax-response"></span>
-							</p>
+						<div id="category-pop" class="tabs-panel" style="display: none;">
+							<ul id="categorychecklist-pop" class="categorychecklist form-no-clear" >
+								<?php $popular_ids = wp_popular_terms_checklist( 'category' ); ?>
+							</ul>
 						</div>
-					<?php endif; ?>
-				</div>
-				</div>
-			</div>

-			<div id="tagsdiv-post_tag" class="postbox">
-				<div class="handlediv" title="<?php esc_attr_e( 'Click to toggle' ); ?>"><br /></div>
-				<h3><span><?php _e('Tags'); ?></span></h3>
-				<div class="inside">
-					<div class="tagsdiv" id="post_tag">
-						<div class="jaxtag">
-							<label class="screen-reader-text" for="newtag"><?php _e('Tags'); ?></label>
-							<input type="hidden" name="tax_input[post_tag]" class="the-tags" id="tax-input[post_tag]" value="" />
-							<div class="ajaxtag">
-								<input type="text" name="newtag[post_tag]" class="newtag form-input-tip" size="16" autocomplete="off" value="" />
-								<input type="button" class="button tagadd" value="<?php esc_attr_e('Add'); ?>" />
+						<div id="category-all" class="tabs-panel">
+							<ul id="categorychecklist" data-wp-lists="list:category" class="categorychecklist form-no-clear">
+								<?php wp_terms_checklist($post_ID, array( 'taxonomy' => 'category', 'popular_cats' => $popular_ids ) ) ?>
+							</ul>
+						</div>
+
+						<?php if ( current_user_can($tax->cap->edit_terms) ) : ?>
+							<div id="category-adder" class="wp-hidden-children">
+								<h4>
+									<a id="category-add-toggle" href="#category-add" class="hide-if-no-js">
+										<?php printf( __( '+ %s' ), $tax->labels->add_new_item ); ?>
+									</a>
+								</h4>
+								<p id="category-add" class="category-add wp-hidden-child">
+									<label class="screen-reader-text" for="newcategory"><?php echo $tax->labels->add_new_item; ?></label>
+									<input type="text" name="newcategory" id="newcategory" class="form-required form-input-tip" value="<?php echo esc_attr( $tax->labels->new_item_name ); ?>" aria-required="true"/>
+									<label class="screen-reader-text" for="newcategory_parent">
+										<?php echo $tax->labels->parent_item_colon; ?>
+									</label>
+									<?php wp_dropdown_categories( array( 'taxonomy' => 'category', 'hide_empty' => 0, 'name' => 'newcategory_parent', 'orderby' => 'name', 'hierarchical' => 1, 'show_option_none' => '&mdash; ' . $tax->labels->parent_item . ' &mdash;' ) ); ?>
+									<input type="button" id="category-add-submit" data-wp-lists="add:categorychecklist:category-add" class="button category-add-submit" value="<?php echo esc_attr( $tax->labels->add_new_item ); ?>" />
+									<?php wp_nonce_field( 'add-category', '_ajax_nonce-add-category', false ); ?>
+									<span id="category-ajax-response"></span>
+								</p>
 							</div>
-						</div>
-						<div class="tagchecklist"></div>
+						<?php endif; ?>
+					</div>
 					</div>
-					<p class="tagcloud-link"><a href="#titlediv" class="tagcloud-link" id="link-post_tag"><?php _e('Choose from the most used tags'); ?></a></p>
 				</div>
-			</div>
+			<?php endif;
+
+			$tax = get_taxonomy( 'post_tag' );
+			if ( current_user_can( $tax->cap->assign_terms ) ) :
+				?>
+				<div id="tagsdiv-post_tag" class="postbox">
+					<div class="handlediv" title="<?php esc_attr_e( 'Click to toggle' ); ?>"><br /></div>
+					<h3><span><?php _e('Tags'); ?></span></h3>
+					<div class="inside">
+						<div class="tagsdiv" id="post_tag">
+							<div class="jaxtag">
+								<label class="screen-reader-text" for="newtag"><?php _e('Tags'); ?></label>
+								<input type="hidden" name="tax_input[post_tag]" class="the-tags" id="tax-input[post_tag]" value="" />
+								<div class="ajaxtag">
+									<input type="text" name="newtag[post_tag]" class="newtag form-input-tip" size="16" autocomplete="off" value="" />
+									<input type="button" class="button tagadd" value="<?php esc_attr_e('Add'); ?>" />
+								</div>
+							</div>
+							<div class="tagchecklist"></div>
+						</div>
+						<p class="tagcloud-link"><a href="#titlediv" class="tagcloud-link" id="link-post_tag"><?php _e('Choose from the most used tags'); ?></a></p>
+					</div>
+				</div>
+			<?php endif; ?>
 		</div>
 	</div>
 	<div class="posting">
--- a/wp-admin/revision.php
+++ b/wp-admin/revision.php
@@ -63,7 +63,7 @@ default :
 	if ( ! $post = get_post( $revision->post_parent ) )
 		break;

-	if ( ! current_user_can( 'read_post', $revision->ID ) || ! current_user_can( 'read_post', $post->ID ) )
+	if ( ! current_user_can( 'read_post', $revision->ID ) || ! current_user_can( 'edit_post', $revision->post_parent ) )
 		break;

 	// Revisions disabled and we're not looking at an autosave
--- a/wp-admin/theme-editor.php
+++ b/wp-admin/theme-editor.php
@@ -68,7 +68,7 @@ if ( empty( $file ) ) {
 	$relative_file = 'style.css';
 	$file = $allowed_files['style.css'];
 } else {
-	$relative_file = $file;
+	$relative_file = wp_unslash( $file );
 	$file = $theme->get_stylesheet_directory() . '/' . $relative_file;
 }

@@ -127,10 +127,12 @@ default:
 <div id="message" class="updated"><p><?php _e( 'File edited successfully.' ) ?></p></div>
 <?php endif;

-$description = get_file_description( $file );
+$file_description = get_file_description( $relative_file );
 $file_show = array_search( $file, array_filter( $allowed_files ) );
-if ( $description != $file_show )
-	$description .= ' <span>(' . $file_show . ')</span>';
+$description = esc_html( $file_description );
+if ( $file_description != $file_show ) {
+	$description .= ' <span>(' . esc_html( $file_show ) . ')</span>';
+}
 ?>
 <div class="wrap">
 <h2><?php echo esc_html( $title ); ?></h2>
@@ -179,9 +181,9 @@ if ( $allowed_files ) :
 		if ( 'style.css' == $filename )
 			echo "\t</ul>\n\t<h3>" . _x( 'Styles', 'Theme stylesheets in theme editor' ) . "</h3>\n\t<ul>\n";

-		$file_description = get_file_description( $absolute_filename );
+		$file_description = esc_html( get_file_description( $filename ) );
 		if ( $file_description != basename( $filename ) )
-			$file_description .= '<br /><span class="nonessential">(' . $filename . ')</span>';
+			$file_description .= '<br /><span class="nonessential">(' . esc_html( $filename ) . ')</span>';

 		if ( $absolute_filename == $file )
 			$file_description = '<span class="highlight">' . $file_description . '</span>';
--- a/wp-admin/update-core.php
+++ b/wp-admin/update-core.php
@@ -237,6 +237,8 @@ function list_plugin_updates() {
 	<tbody class="plugins">
 <?php
 	foreach ( (array) $plugins as $plugin_file => $plugin_data) {
+		$plugin_data = (object) _get_plugin_data_markup_translate( $plugin_file, (array) $plugin_data, false, true );
+
 		$info = plugins_api('plugin_information', array('slug' => $plugin_data->update->slug ));
 		// Get plugin compat for running version of WordPress.
 		if ( isset($info->tested) && version_compare($info->tested, $cur_wp_version, '>=') ) {
--- a/wp-admin/user-edit.php
+++ b/wp-admin/user-edit.php
@@ -202,7 +202,7 @@ include (ABSPATH . 'wp-admin/admin-header.php');
 	<p><strong><?php _e('User updated.') ?></strong></p>
 	<?php endif; ?>
 	<?php if ( $wp_http_referer && !IS_PROFILE_PAGE ) : ?>
-	<p><a href="<?php echo esc_url( $wp_http_referer ); ?>"><?php _e('&larr; Back to Users'); ?></a></p>
+	<p><a href="<?php echo esc_url( wp_validate_redirect( esc_url_raw( $wp_http_referer ), self_admin_url( 'users.php' ) ) ); ?>"><?php _e('&larr; Back to Users'); ?></a></p>
 	<?php endif; ?>
 </div>
 <?php endif; ?>
--- a/wp-admin/user-new.php
+++ b/wp-admin/user-new.php
@@ -72,7 +72,7 @@ if ( isset($_REQUEST['action']) && 'adduser' == $_REQUEST['action'] ) {
 			add_existing_user_to_blog( array( 'user_id' => $user_id, 'role' => $_REQUEST[ 'role' ] ) );
 			$redirect = add_query_arg( array('update' => 'addnoconfirmation'), 'user-new.php' );
 		} else {
-			$newuser_key = substr( md5( $user_id ), 0, 5 );
+			$newuser_key = wp_generate_password( 20, false );
 			add_option( 'new_user_' . $newuser_key, array( 'user_id' => $user_id, 'email' => $user_details->user_email, 'role' => $_REQUEST[ 'role' ] ) );

 			$roles = get_editable_roles();
--- a/wp-admin/widgets.php
+++ b/wp-admin/widgets.php
@@ -17,6 +17,8 @@ if ( ! current_user_can('edit_theme_options') )

 $widgets_access = get_user_setting( 'widgets_access' );
 if ( isset($_GET['widgets-access']) ) {
+	check_admin_referer( 'widgets-access' );
+
 	$widgets_access = 'on' == $_GET['widgets-access'] ? 'on' : 'off';
 	set_user_setting( 'widgets_access', $widgets_access );
 }
--- a/wp-includes/class-phpmailer.php
+++ b/wp-includes/class-phpmailer.php
--- a/wp-includes/class-smtp.php
+++ b/wp-includes/class-smtp.php
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -123,6 +123,24 @@ final class WP_Customize_Manager {

 		$this->theme = wp_get_theme( isset( $_REQUEST['theme'] ) ? $_REQUEST['theme'] : null );

+		/*
+		 * Clear incoming post data if the user lacks a CSRF token (nonce). Note that the customizer
+		 * application will inject the customize_preview_nonce query parameter into all Ajax requests.
+		 * For similar behavior elsewhere in WordPress, see rest_cookie_check_errors() which logs out
+		 * a user when a valid nonce isn't present.
+		 */
+		$has_post_data_nonce = (
+			check_ajax_referer( 'preview-customize_' . $this->get_stylesheet(), 'nonce', false )
+			||
+			check_ajax_referer( 'save-customize_' . $this->get_stylesheet(), 'nonce', false )
+			||
+			check_ajax_referer( 'preview-customize_' . $this->get_stylesheet(), 'customize_preview_nonce', false )
+		);
+		if ( ! $has_post_data_nonce ) {
+			unset( $_POST['customized'] );
+			unset( $_REQUEST['customized'] );
+		}
+
 		if ( $this->is_theme_active() ) {
 			// Once the theme is loaded, we'll validate it.
 			add_action( 'after_setup_theme', array( $this, 'after_setup_theme' ) );
--- a/wp-includes/class-wp-theme.php
+++ b/wp-includes/class-wp-theme.php
@@ -650,8 +650,9 @@ final class WP_Theme implements ArrayAccess {
 	private function markup_header( $header, $value, $translate ) {
 		switch ( $header ) {
 			case 'Name' :
-				if ( empty( $value ) )
-					$value = $this->get_stylesheet();
+				if ( empty( $value ) ) {
+					$value = esc_html( $this->get_stylesheet() );
+				}
 				break;
 			case 'Description' :
 				$value = wptexturize( $value );
--- a/wp-includes/class-wp-xmlrpc-server.php
+++ b/wp-includes/class-wp-xmlrpc-server.php
@@ -273,6 +273,11 @@ class wp_xmlrpc_server extends IXR_Server {
 			if ( isset($meta['id']) ) {
 				$meta['id'] = (int) $meta['id'];
 				$pmeta = get_metadata_by_mid( 'post', $meta['id'] );
+
+				if ( ! $pmeta || $pmeta->post_id != $post_id ) {
+					continue;
+				}
+
 				if ( isset($meta['key']) ) {
 					$meta['key'] = wp_unslash( $meta['key'] );
 					if ( $meta['key'] !== $pmeta->meta_key )
@@ -1049,10 +1054,31 @@ class wp_xmlrpc_server extends IXR_Server {
 	 * @param array $content_struct Post data to insert.
 	 */
 	protected function _insert_post( $user, $content_struct ) {
-		$defaults = array( 'post_status' => 'draft', 'post_type' => 'post', 'post_author' => 0,
-			'post_password' => '', 'post_excerpt' => '', 'post_content' => '', 'post_title' => '' );
+		$defaults = array(
+			'post_status'    => 'draft',
+			'post_type'      => 'post',
+			'post_author'    => null,
+			'post_password'  => null,
+			'post_excerpt'   => null,
+			'post_content'   => null,
+			'post_title'     => null,
+			'post_date'      => null,
+			'post_date_gmt'  => null,
+			'post_format'    => null,
+			'post_name'      => null,
+			'post_thumbnail' => null,
+			'post_parent'    => null,
+			'ping_status'    => null,
+			'comment_status' => null,
+			'custom_fields'  => null,
+			'terms_names'    => null,
+			'terms'          => null,
+			'sticky'         => null,
+			'enclosure'      => null,
+			'ID'             => null,
+		);

-		$post_data = wp_parse_args( $content_struct, $defaults );
+		$post_data = wp_parse_args( array_intersect_key( $content_struct, $defaults ), $defaults );

 		$post_type = get_post_type_object( $post_data['post_type'] );
 		if ( ! $post_type )
@@ -1232,9 +1258,6 @@ class wp_xmlrpc_server extends IXR_Server {

 			$post_data['tax_input'] = $terms;
 			unset( $post_data['terms'], $post_data['terms_names'] );
-		} else {
-			// do not allow direct submission of 'tax_input', clients must use 'terms' and/or 'terms_names'
-			unset( $post_data['tax_input'], $post_data['post_category'], $post_data['tags_input'] );
 		}

 		if ( isset( $post_data['post_format'] ) ) {
--- a/wp-includes/feed.php
+++ b/wp-includes/feed.php
@@ -395,7 +395,7 @@ function rss_enclosure() {
 				$t = preg_split('/[ \t]/', trim($enclosure[2]) );
 				$type = $t[0];

-				echo apply_filters('rss_enclosure', '<enclosure url="' . trim(htmlspecialchars($enclosure[0])) . '" length="' . trim($enclosure[1]) . '" type="' . $type . '" />' . "\n");
+				echo apply_filters( 'rss_enclosure', '<enclosure url="' . esc_url( trim( $enclosure[0] ) ) . '" length="' . absint( trim( $enclosure[1] ) ) . '" type="' . esc_attr( $type ) . '" />' . "\n" );
 			}
 		}
 	}
@@ -426,7 +426,7 @@ function atom_enclosure() {
 		if ($key == 'enclosure') {
 			foreach ( (array) $val as $enc ) {
 				$enclosure = explode("\n", $enc);
-				echo apply_filters('atom_enclosure', '<link href="' . trim(htmlspecialchars($enclosure[0])) . '" rel="enclosure" length="' . trim($enclosure[1]) . '" type="' . trim($enclosure[2]) . '" />' . "\n");
+				echo apply_filters( 'atom_enclosure', '<link href="' . esc_url( trim( $enclosure[0] ) ) . '" rel="enclosure" length="' . absint( trim( $enclosure[1] ) ) . '" type="' . esc_attr( trim( $enclosure[2] ) ) . '" />' . "\n" );
 			}
 		}
 	}
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -966,7 +966,8 @@ function remove_accents($string) {
 * operating systems and special characters requiring special escaping
 * to manipulate at the command line. Replaces spaces and consecutive
 * dashes with a single dash. Trims period, dash and underscore from beginning
- * and end of filename.
+ * and end of filename. It is not guaranteed that this function will return a
+ * filename that is allowed to be uploaded.
 *
 * @since 2.1.0
 *
@@ -989,6 +990,14 @@ function sanitize_file_name( $filename ) {
 	$filename = preg_replace('/[\s-]+/', '-', $filename);
 	$filename = trim($filename, '.-_');

+	if ( false === strpos( $filename, '.' ) ) {
+		$mime_types = wp_get_mime_types();
+		$filetype = wp_check_filetype( 'test.' . $filename, $mime_types );
+		if ( $filetype['ext'] === $filename ) {
+			$filename = 'unnamed-file.' . $filetype['ext'];
+		}
+	}
+
 	// Split the filename into a base and extension[s]
 	$parts = explode('.', $filename);

--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -1874,7 +1874,7 @@ function wp_check_filetype( $filename, $mimes = null ) {
 * If it's determined that the extension does not match the file's real type,
 * then the "proper_filename" value will be set with a proper filename and extension.
 *
- * Currently this function only supports validating images known to getimagesize().
+ * Currently this function only supports renaming images validated via wp_get_image_mime().
 *
 * @since 3.0.0
 *
@@ -1895,14 +1895,15 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 	if ( ! file_exists( $file ) )
 		return compact( 'ext', 'type', 'proper_filename' );

-	// We're able to validate images using GD
-	if ( $type && 0 === strpos( $type, 'image/' ) && function_exists('getimagesize') ) {
+	// Validate image types.
+	if ( $type && 0 === strpos( $type, 'image/' ) ) {

 		// Attempt to figure out what type of image it actually is
-		$imgstats = @getimagesize( $file );
+		$real_mime = wp_get_image_mime( $file );

-		// If getimagesize() knows what kind of image it really is and if the real MIME doesn't match the claimed MIME
-		if ( !empty($imgstats['mime']) && $imgstats['mime'] != $type ) {
+		if ( ! $real_mime ) {
+			$type = $ext = false;
+		} elseif ( $real_mime != $type ) {
 			// This is a simplified array of MIMEs that getimagesize() can detect and their extensions
 			// You shouldn't need to use this filter, but it's here just in case
 			$mime_to_ext = apply_filters( 'getimagesize_mimes_to_exts', array(
@@ -1914,10 +1915,10 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 			) );

 			// Replace whatever is after the last period in the filename with the correct extension
-			if ( ! empty( $mime_to_ext[ $imgstats['mime'] ] ) ) {
+			if ( ! empty( $mime_to_ext[ $real_mime ] ) ) {
 				$filename_parts = explode( '.', $filename );
 				array_pop( $filename_parts );
-				$filename_parts[] = $mime_to_ext[ $imgstats['mime'] ];
+				$filename_parts[] = $mime_to_ext[ $real_mime ];
 				$new_filename = implode( '.', $filename_parts );

 				if ( $new_filename != $filename )
@@ -1926,8 +1927,20 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 				// Redefine the extension / MIME
 				$wp_filetype = wp_check_filetype( $new_filename, $mimes );
 				extract( $wp_filetype );
+			} else {
+				$type = $ext = false;
 			}
 		}
+	} elseif ( function_exists( 'finfo_file' ) ) {
+		// Use finfo_file if available to validate non-image files.
+		$finfo = finfo_open( FILEINFO_MIME_TYPE );
+		$real_mime = finfo_file( $finfo, $file );
+		finfo_close( $finfo );
+
+		// If the extension does not match the file's real type, return false.
+		if ( $real_mime !== $type ) {
+			$type = $ext = false;
+		}
 	}

 	// Let plugins try and validate other types of files
@@ -1935,6 +1948,38 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 	return apply_filters( 'wp_check_filetype_and_ext', compact( 'ext', 'type', 'proper_filename' ), $file, $filename, $mimes );
 }

+/**
+ * Returns the real mime type of an image file.
+ *
+ * This depends on exif_imagetype() or getimagesize() to determine real mime types.
+ *
+ * @since 4.7.1
+ *
+ * @param string $file Full path to the file.
+ * @return string|false The actual mime type or false if the type cannot be determined.
+ */
+function wp_get_image_mime( $file ) {
+	/*
+	 * Use exif_imagetype() to check the mimetype if available or fall back to
+	 * getimagesize() if exif isn't avaialbe. If either function throws an Exception
+	 * we assume the file could not be validated.
+	 */
+	try {
+		if ( is_callable( 'exif_imagetype' ) ) {
+			$mime = image_type_to_mime_type( exif_imagetype( $file ) );
+		} elseif ( function_exists( 'getimagesize' ) ) {
+			$imagesize = getimagesize( $file );
+			$mime = ( isset( $imagesize['mime'] ) ) ? $imagesize['mime'] : false;
+		} else {
+			$mime = false;
+		}
+	} catch ( Exception $e ) {
+		$mime = false;
+	}
+
+	return $mime;
+}
+
 /**
 * Retrieve list of mime types and file extensions.
 *
@@ -2059,8 +2104,9 @@ function get_allowed_mime_types( $user = null ) {
 	if ( function_exists( 'current_user_can' ) )
 		$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );

-	if ( empty( $unfiltered ) )
-		unset( $t['htm|html'] );
+	if ( empty( $unfiltered ) ) {
+		unset( $t['htm|html'], $t['js'] );
+	}

 	return apply_filters( 'upload_mimes', $t, $user );
 }
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -1935,12 +1935,14 @@ function language_attributes($doctype = 'html') {
 	if ( function_exists( 'is_rtl' ) && is_rtl() )
 		$attributes[] = 'dir="rtl"';

-	if ( $lang = get_bloginfo('language') ) {
-		if ( get_option('html_type') == 'text/html' || $doctype == 'html' )
-			$attributes[] = "lang=\"$lang\"";
+	if ( $lang = get_bloginfo( 'language' ) ) {
+		if ( get_option( 'html_type' ) == 'text/html' || $doctype == 'html' ) {
+			$attributes[] = 'lang="' . esc_attr( $lang ) . '"';
+		}

-		if ( get_option('html_type') != 'text/html' || $doctype == 'xhtml' )
-			$attributes[] = "xml:lang=\"$lang\"";
+		if ( get_option( 'html_type' ) != 'text/html' || $doctype == 'xhtml' ) {
+			$attributes[] = 'xml:lang="' . esc_attr( $lang ) . '"';
+		}
 	}

 	$output = implode(' ', $attributes);
--- a/wp-includes/js/mediaelement/flashmediaelement.swf
+++ b/wp-includes/js/mediaelement/flashmediaelement.swf
--- a/wp-includes/js/mediaelement/silverlightmediaelement.xap
+++ b/wp-includes/js/mediaelement/silverlightmediaelement.xap
--- a/wp-includes/js/plupload/handlers.js
+++ b/wp-includes/js/plupload/handlers.js
@@ -324,15 +324,24 @@ function uploadError(fileObj, errorCode, message, uploader) {
 	}
 }

-function uploadSizeError( up, file, over100mb ) {
-	var message;
+function uploadSizeError( up, file ) {
+	var message, errorDiv;

-	if ( over100mb )
-		message = pluploadL10n.big_upload_queued.replace('%s', file.name) + ' ' + pluploadL10n.big_upload_failed.replace('%1$s', '<a class="uploader-html" href="#">').replace('%2$s', '</a>');
-	else
-		message = pluploadL10n.file_exceeds_size_limit.replace('%s', file.name);
+	message = pluploadL10n.file_exceeds_size_limit.replace('%s', file.name);

-	jQuery('#media-items').append('<div id="media-item-' + file.id + '" class="media-item error"><p>' + message + '</p></div>');
+	// Construct the error div.
+	errorDiv = jQuery( '<div />' )
+		.attr( {
+			'id':    'media-item-' + file.id,
+			'class': 'media-item error'
+		} )
+		.append(
+			jQuery( '<p />' )
+				.text( message )
+		);
+
+	// Append the error.
+	jQuery('#media-items').append( errorDiv );
 	up.removeFile(file);
 }

--- a/wp-includes/js/plupload/handlers.min.js
+++ b/wp-includes/js/plupload/handlers.min.js
--- a/wp-includes/js/wplink.js
+++ b/wp-includes/js/wplink.js
@@ -165,6 +165,13 @@ var wpLink;

 			attrs = wpLink.getAttrs();

+			var parser = document.createElement( 'a' );
+			parser.href = attrs.href;
+
+			if ( 'javascript:' === parser.protocol || 'data:' === parser.protocol ) { // jshint ignore:line
+				attrs.href = '';
+			}
+
 			// If there's no href, return.
 			if ( ! attrs.href || attrs.href == 'http://' )
 				return;
@@ -175,7 +182,7 @@ var wpLink;
 			if ( attrs.title )
 				html += ' title="' + attrs.title + '"';
 			if ( attrs.target )
-				html += ' target="' + attrs.target + '"';
+				html += ' rel="noopener" target="' + attrs.target + '"';

 			html += '>';

@@ -221,6 +228,13 @@ var wpLink;
 			tinyMCEPopup.restoreSelection();
 			e = ed.dom.getParent(ed.selection.getNode(), 'A');

+			var parser = document.createElement( 'a' );
+			parser.href = attrs.href;
+
+			if ( 'javascript:' === parser.protocol || 'data:' === parser.protocol ) { // jshint ignore:line
+				attrs.href = '';
+			}
+
 			// If the values are empty, unlink and return
 			if ( ! attrs.href || attrs.href == 'http://' ) {
 				if ( e ) {
--- a/wp-includes/js/wplink.min.js
+++ b/wp-includes/js/wplink.min.js
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -715,7 +715,7 @@ function wpmu_validate_blog_signup( $blogname, $blog_title, $user = '' ) {
 function wpmu_signup_blog( $domain, $path, $title, $user, $user_email, $meta = array() )  {
 	global $wpdb;

-	$key = substr( md5( time() . rand() . $domain ), 0, 16 );
+	$key = substr( md5( time() . wp_rand() . $domain ), 0, 16 );
 	$meta = serialize($meta);

 	$wpdb->insert( $wpdb->signups, array(
@@ -751,7 +751,7 @@ function wpmu_signup_user( $user, $user_email, $meta = array() ) {
 	// Format data
 	$user = preg_replace( '/\s+/', '', sanitize_user( $user, true ) );
 	$user_email = sanitize_email( $user_email );
-	$key = substr( md5( time() . rand() . $user_email ), 0, 16 );
+	$key = substr( md5( time() . wp_rand() . $user_email ), 0, 16 );
 	$meta = serialize($meta);

 	$wpdb->insert( $wpdb->signups, array(
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -755,10 +755,14 @@ function auth_redirect() {
 		}
 	}

-	if ( is_user_admin() )
-		$scheme = 'logged_in';
-	else
-		$scheme = apply_filters( 'auth_redirect_scheme', '' );
+	/**
+	 * Filters the authentication redirect scheme.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $scheme Authentication redirect scheme. Default empty.
+	 */
+	$scheme = apply_filters( 'auth_redirect_scheme', '' );

 	if ( $user_id = wp_validate_auth_cookie( '',  $scheme) ) {
 		do_action('auth_redirect', $user_id);
@@ -965,7 +969,7 @@ if ( !function_exists('wp_validate_redirect') ) :
 * @return string redirect-sanitized URL
 **/
 function wp_validate_redirect($location, $default = '') {
-	$location = trim( $location );
+	$location = trim( $location, " \t\n\r\0\x08\x0B" );
 	// browsers will assume 'http' is your protocol, and will obey a redirect to a URL starting with '//'
 	if ( substr($location, 0, 2) == '//' )
 		$location = 'http:' . $location;
--- a/wp-includes/post-template.php
+++ b/wp-includes/post-template.php
@@ -1204,7 +1204,7 @@ function wp_get_attachment_link( $id = 0, $size = 'thumbnail', $permalink = fals
 	if ( trim( $link_text ) == '' )
 		$link_text = $_post->post_title;

-	return apply_filters( 'wp_get_attachment_link', "<a href='$url'>$link_text</a>", $id, $size, $permalink, $icon, $text );
+	return apply_filters( 'wp_get_attachment_link', "<a href='" . esc_url( $url ) . "'>$link_text</a>", $id, $size, $permalink, $icon, $text );
 }

 /**
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -3501,10 +3501,10 @@ function get_page_by_path($page_path, $output = OBJECT, $post_type = 'page') {
 	$page_path = str_replace('%2F', '/', $page_path);
 	$page_path = str_replace('%20', ' ', $page_path);
 	$parts = explode( '/', trim( $page_path, '/' ) );
-	$parts = esc_sql( $parts );
 	$parts = array_map( 'sanitize_title_for_query', $parts );
+	$escaped_parts = esc_sql( $parts );

-	$in_string = "'". implode( "','", $parts ) . "'";
+	$in_string = "'". implode( "','", $escaped_parts ) . "'";
 	$post_type_sql = esc_sql( $post_type );
 	$pages = $wpdb->get_results( "SELECT ID, post_name, post_parent, post_type FROM $wpdb->posts WHERE post_name IN ($in_string) AND (post_type = '$post_type_sql' OR post_type = 'attachment')", OBJECT_K );

--- a/wp-includes/query.php
+++ b/wp-includes/query.php
@@ -2675,14 +2675,15 @@ class WP_Query {

 		if ( 'any' == $post_type ) {
 			$in_search_post_types = get_post_types( array('exclude_from_search' => false) );
-			if ( empty( $in_search_post_types ) )
+			if ( empty( $in_search_post_types ) ) {
 				$where .= ' AND 1=0 ';
-			else
-				$where .= " AND $wpdb->posts.post_type IN ('" . join("', '", $in_search_post_types ) . "')";
+			} else {
+				$where .= " AND {$wpdb->posts}.post_type IN ('" . join( "', '", array_map( 'esc_sql', $in_search_post_types ) ) . "')";
+			}
 		} elseif ( !empty( $post_type ) && is_array( $post_type ) ) {
-			$where .= " AND $wpdb->posts.post_type IN ('" . join("', '", $post_type) . "')";
+			$where .= " AND {$wpdb->posts}.post_type IN ('" . join("', '", esc_sql( $post_type ) ) . "')";
 		} elseif ( ! empty( $post_type ) ) {
-			$where .= " AND $wpdb->posts.post_type = '$post_type'";
+			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_type = %s", $post_type );
 			$post_type_object = get_post_type_object ( $post_type );
 		} elseif ( $this->is_attachment ) {
 			$where .= " AND $wpdb->posts.post_type = 'attachment'";
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
 *
 * @global string $wp_version
 */
-$wp_version = '3.8.14';
+$wp_version = '3.8.25';

 /**
 * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -911,8 +911,9 @@ class wpdb {
 	}

 	/**
-	 * Real escape, using mysql_real_escape_string()
+	 * Real escape, using mysqli_real_escape_string() or mysql_real_escape_string()
 	 *
+	 * @see mysqli_real_escape_string()
 	 * @see mysql_real_escape_string()
 	 * @since 2.8.0
 	 * @access private
@@ -921,12 +922,20 @@ class wpdb {
 	 * @return string escaped
 	 */
 	function _real_escape( $string ) {
-		if ( $this->dbh )
-			return mysql_real_escape_string( $string, $this->dbh );
+		if ( $this->dbh ) {
+			$escaped = mysql_real_escape_string( $string, $this->dbh );
+		} else {
+			$class = get_class( $this );
+			if ( function_exists( '__' ) ) {
+				/* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
+				_doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
+			} else {
+				_doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
+			}
+			$escaped = addslashes( $string );
+		}

-		$class = get_class( $this );
-		_doing_it_wrong( $class, "$class must set a database connection for use with escaping.", E_USER_NOTICE );
-		return addslashes( $string );
+		return $this->add_placeholder_escape( $escaped );
 	}

 	/**
@@ -1000,55 +1009,120 @@ class wpdb {
 	/**
 	 * Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
 	 *
-	 * The following directives can be used in the query format string:
+	 * The following placeholders can be used in the query string:
 	 *   %d (integer)
 	 *   %f (float)
 	 *   %s (string)
-	 *   %% (literal percentage sign - no argument needed)
 	 *
-	 * All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
-	 * Literals (%) as parts of the query must be properly written as %%.
+	 * All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
 	 *
-	 * This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
-	 * Does not support sign, padding, alignment, width or precision specifiers.
-	 * Does not support argument numbering/swapping.
+	 * For compatibility with old behavior, numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes
+	 * added by this function, so should be passed with appropriate quotes around them for your usage.
 	 *
-	 * May be called like {@link http://php.net/sprintf sprintf()} or like {@link http://php.net/vsprintf vsprintf()}.
+	 * Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards (for example,
+	 * to use in LIKE syntax) must be passed via a substitution argument containing the complete LIKE string, these
+	 * cannot be inserted directly in the query string. Also see {@see esc_like()}.
 	 *
-	 * Both %d and %s should be left unquoted in the query string.
+	 * Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination
+	 * of the two is not supported.
 	 *
-	 * <code>
-	 * wpdb::prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 )
-	 * wpdb::prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
-	 * </code>
+	 * Examples:
+	 *     $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s", array( 'foo', 1337, '%bar' ) );
+	 *     $wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
 	 *
-	 * @link http://php.net/sprintf Description of syntax.
+	 * @link https://secure.php.net/sprintf Description of syntax.
 	 * @since 2.3.0
 	 *
-	 * @param string $query Query statement with sprintf()-like placeholders
-	 * @param array|mixed $args The array of variables to substitute into the query's placeholders if being called like
-	 * 	{@link http://php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
-	 * 	being called like {@link http://php.net/sprintf sprintf()}.
-	 * @param mixed $args,... further variables to substitute into the query's placeholders if being called like
-	 * 	{@link http://php.net/sprintf sprintf()}.
-	 * @return null|false|string Sanitized query string, null if there is no query, false if there is an error and string
-	 * 	if there was something to prepare
+	 * @param string      $query    Query statement with sprintf()-like placeholders
+	 * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called with an array of arguments,
+	 *                              or the first variable to substitute into the query's placeholders if being called with individual arguments.
+	 * @param mixed       $args,... further variables to substitute into the query's placeholders if being called wih individual arguments.
+	 * @return string|void Sanitized query string, if there is a query to prepare.
 	 */
-	function prepare( $query, $args ) {
-		if ( is_null( $query ) )
+	public function prepare( $query, $args ) {
+		if ( is_null( $query ) ) {
 			return;
+		}
+
+		// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
+		if ( strpos( $query, '%' ) === false ) {
+			wp_load_translations_early();
+			_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
+		}

 		$args = func_get_args();
 		array_shift( $args );
-		// If args were passed as an array (as in vsprintf), move them up
-		if ( isset( $args[0] ) && is_array($args[0]) )
+
+		// If args were passed as an array (as in vsprintf), move them up.
+		$passed_as_array = false;
+		if ( is_array( $args[0] ) && count( $args ) == 1 ) {
+			$passed_as_array = true;
 			$args = $args[0];
-		$query = str_replace( "'%s'", '%s', $query ); // in case someone mistakenly already singlequoted it
-		$query = str_replace( '"%s"', '%s', $query ); // doublequote unquoting
-		$query = preg_replace( '|(?<!%)%f|' , '%F', $query ); // Force floats to be locale unaware
-		$query = preg_replace( '|(?<!%)%s|', "'%s'", $query ); // quote the strings, avoiding escaped strings like %%s
+		}
+
+		foreach ( $args as $arg ) {
+			if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
+				wp_load_translations_early();
+				_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'Unsupported value type (%s).' ), gettype( $arg ) ), '4.8.2' );
+			}
+		}
+
+		/*
+		 * Specify the formatting allowed in a placeholder. The following are allowed:
+		 *
+		 * - Sign specifier. eg, $+d
+		 * - Numbered placeholders. eg, %1$s
+		 * - Padding specifier, including custom padding characters. eg, %05s, %'#5s
+		 * - Alignment specifier. eg, %05-s
+		 * - Precision specifier. eg, %.2f
+		 */
+		$allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
+
+		/*
+		 * If a %s placeholder already has quotes around it, removing the existing quotes and re-inserting them
+		 * ensures the quotes are consistent.
+		 *
+		 * For backwards compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
+		 * used in the middle of longer strings, or as table name placeholders.
+		 */
+		$query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
+		$query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
+		$query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.
+
+		$query = preg_replace( "/(?<!%)(%($allowed_format)?f)/" , '%\\2F', $query ); // Force floats to be locale unaware.
+
+		$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
+
+		// Count the number of valid placeholders in the query.
+		$placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
+
+		if ( count( $args ) !== $placeholders ) {
+			if ( 1 === $placeholders && $passed_as_array ) {
+				// If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
+				wp_load_translations_early();
+				_doing_it_wrong( 'wpdb::prepare', __( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ), '4.9.0' );
+
+				return;
+			} else {
+				/*
+				 * If we don't have the right number of placeholders, but they were passed as individual arguments,
+				 * or we were expecting multiple arguments in an array, throw a warning.
+				 */
+				wp_load_translations_early();
+				_doing_it_wrong( 'wpdb::prepare',
+					/* translators: 1: number of placeholders, 2: number of arguments passed */
+					sprintf( __( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
+						$placeholders,
+						count( $args ) ),
+					'4.8.3'
+				);
+			}
+		}
+
 		array_walk( $args, array( $this, 'escape_by_ref' ) );
-		return @vsprintf( $query, $args );
+		$query = @vsprintf( $query, $args );
+
+		return $this->add_placeholder_escape( $query );
 	}

 	/**
@@ -1314,6 +1388,64 @@ class wpdb {
 		return $return_val;
 	}

+	/**
+	 * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
+	 *
+	 * @since 4.8.3
+	 *
+	 * @return string String to escape placeholders.
+	 */
+	public function placeholder_escape() {
+		static $placeholder;
+
+		if ( ! $placeholder ) {
+			// If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
+			$algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
+			// Old WP installs may not have AUTH_SALT defined.
+			$salt = defined( 'AUTH_SALT' ) && AUTH_SALT ? AUTH_SALT : (string) rand();
+
+			$placeholder = '{' . hash_hmac( $algo, uniqid( $salt, true ), $salt ) . '}';
+		}
+
+		/*
+		 * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
+		 * else attached to this filter will recieve the query with the placeholder string removed.
+		 */
+		if ( ! has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
+			add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
+		}
+
+		return $placeholder;
+	}
+
+	/**
+	 * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
+	 *
+	 * @since 4.8.3
+	 *
+	 * @param string $query The query to escape.
+	 * @return string The query with the placeholder escape string inserted where necessary.
+	 */
+	public function add_placeholder_escape( $query ) {
+		/*
+		 * To prevent returning anything that even vaguely resembles a placeholder,
+		 * we clobber every % we can find.
+		 */
+		return str_replace( '%', $this->placeholder_escape(), $query );
+	}
+
+	/**
+	 * Removes the placeholder escape strings from a query.
+	 *
+	 * @since 4.8.3
+	 *
+	 * @param string $query The query from which the placeholder will be removed.
+	 * @return string The query with the placeholder removed.
+	 */
+	public function remove_placeholder_escape( $query ) {
+		return str_replace( $this->placeholder_escape(), '%', $query );
+	}
+
 	/**
 	 * Insert a row into a table.
 	 *
--- a/wp-mail.php
+++ b/wp-mail.php
@@ -14,6 +14,12 @@ require(dirname(__FILE__) . '/wp-load.php');
 if ( ! apply_filters( 'enable_post_by_email_configuration', true ) )
 	wp_die( __( 'This action has been disabled by the administrator.' ) );

+$mailserver_url = get_option( 'mailserver_url' );
+
+if ( 'mail.example.com' === $mailserver_url || empty( $mailserver_url ) ) {
+	wp_die( __( 'This action has been disabled by the administrator.' ), 403 );
+}
+
 /**
 * Fires to allow a plugin to do a complete takeover of Post by Email.
 *