diff --git a/system/libraries/Input.php b/system/libraries/Input.php
index dc5b5e5..2682ce3 100644
--- a/system/libraries/Input.php
+++ b/system/libraries/Input.php
@@ -728,7 +728,7 @@
 		 * Becomes: &lt;blink&gt;
 		 *
 		 */
-		$naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';
+		$naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|isindex|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';
 		$str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);
 
 		/*