diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
index dd40d93d2b..b32f012542 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
@@ -344,8 +344,10 @@ abstract class WP_REST_Controller {
 
 		$schema = $this->get_item_schema();
 
-		foreach ( $schema['properties'] as &$property ) {
-			unset( $property['arg_options'] );
+		if ( ! empty( $schema['properties'] ) ) {
+			foreach ( $schema['properties'] as &$property ) {
+				unset( $property['arg_options'] );
+			}
 		}
 
 		return $schema;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 6b432ebdde..80220394cd 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.4-beta2-47327';
+$wp_version = '5.4-beta2-47328';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.