Ticket #37134: 37134.3.diff

wp-includes/kses.php

@@ -1951 +1951 @@
         $css = wp_kses_no_null( $css );
         $css = str_replace( array( "\n", "\r", "\t" ), '', $css );
 
-        if ( preg_match( '%[\\\\(&=}]|/\*%', $css ) ) { // remove any inline css containing \ ( & } = or comments
+        /**
+         * Filters list of allowed CSS attributes.
+         *
+         * @param string Pattern of unallowed characters in CSS rules.
+         */
+        $unallowed_chars = apply_filters('safe_style_unallowed_chars', '%[\\\\(&=}]|/\*%' ); // remove any inline css containing \ ( & } = or comments
+        if ( preg_match( $unallowed_chars, $css ) ) {
                 return '';
         }