Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 11556)
+++ wp-includes/formatting.php	(working copy)
@@ -2266,7 +2266,7 @@
  * @return string text, safe for inclusion in LIKE query.
  */
 function like_escape($text) {
-	return str_replace(array("%", "_"), array("\\%", "\\_"), $text);
+	return addcslashes($text, '%_');
 }
 
 /**