Ticket #14292: 14292.2.diff

wp-includes/canonical.php

@@ -344 +344 @@
         if ( !$redirect_url || $redirect_url == $requested_url )
                 return false;
 
+        // Hex encoded octets are case-insensitive.
+        if ( false !== strpos($requested_url, '%') ) {
+                function lowercase_octets($matches) {
+                        return strtolower($matches[0]);
+                }
+                $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
+        }
+
         // Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning FALSE
         $redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);