Index: wp-includes/canonical.php
===================================================================
--- wp-includes/canonical.php	(revision 18666)
+++ wp-includes/canonical.php	(working copy)
@@ -280,6 +280,7 @@
 				unset( $_parsed_query['name'] );
 		}
 
+		$_parsed_query = array_map( 'urlencode', $_parsed_query );
 		$redirect_url = add_query_arg( $_parsed_query, $redirect_url );
 	}