Ticket #21167: 21167.2.patch

wp-includes/rewrite.php

@@ -1251 +1251 @@
                         }
                 }
 
+                $permalink_structure = preg_quote( $permalink_structure );
+
                 //get everything up to the first rewrite tag
                 $front = substr($permalink_structure, 0, strpos($permalink_structure, '%'));
                 //build an array of the tags (note that said array ends up being in $tokens[0])