diff --git a/src/security/security_manager.c b/src/security/security_manager.c
index 0246dd88bd..6f0becdb78 100644
--- a/src/security/security_manager.c
+++ b/src/security/security_manager.c
@@ -107,7 +107,9 @@ virSecurityManagerPtr virSecurityManagerNew(const char *name,
 
 void *virSecurityManagerGetPrivateData(virSecurityManagerPtr mgr)
 {
-    return ((char*)mgr) + sizeof(mgr);
+    /* This accesses the memory just beyond mgr, which was allocated
+     * via VIR_ALLOC_VAR earlier.  */
+    return mgr + 1;
 }