Ticket #20449: 20449.2.patch

wp-admin/includes/file.php

@@ -83 +83 @@
         $siteurl = get_option( 'siteurl' );
         if ( ! empty( $home ) && 0 !== strcasecmp( $home, $siteurl ) ) {
                 $wp_path_rel_to_home = str_ireplace( $home, '', $siteurl ); /* $siteurl - $home */
-                $pos = strripos( str_replace( '\\', '/', $_SERVER['SCRIPT_FILENAME'] ), $wp_path_rel_to_home);
+                $pos = strripos( str_replace( '\\', '/', $_SERVER['SCRIPT_FILENAME'] ), trailingslashit( $wp_path_rel_to_home ) );
                 $home_path = substr( $_SERVER['SCRIPT_FILENAME'], 0, $pos );
                 $home_path = trailingslashit( $home_path );
         } else {