Ticket #21167: 21167.patch

wp-includes/rewrite.php

@@ -1251 +1251 @@
                         }
                 }
 
+                //escape regex special characters in permalink structure
+                foreach ( array( '.', '+', '$', '(', ')' ) as $special_char )
+                        $permalink_structure = str_replace( $special_char, '\\' . $special_char, $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])