diff --git a/system/core/Security.php b/system/core/Security.php
index 15cb376..8acab01 100644
--- a/system/core/Security.php
+++ b/system/core/Security.php
@@ -683,7 +683,7 @@
 			$attribs = array();
 
 			// find occurrences of illegal attribute strings with quotes (042 and 047 are octal quotes)
-			preg_match_all('/\W('.implode('|', $evil_attributes).')\s*=\s*(\042|\047)([^\\2]*?)(\\2)/is', $str, $matches, PREG_SET_ORDER);
+			preg_match_all('/(?<!\w)('.implode('|', $evil_attributes).')\s*=\s*(\042|\047)([^\\2]*?)(\\2)/is', $str, $matches, PREG_SET_ORDER);
 
 			foreach ($matches as $attr)
 			{
@@ -691,7 +691,7 @@
 			}
 
 			// find occurrences of illegal attribute strings without quotes
-			preg_match_all('/\W('.implode('|', $evil_attributes).')\s*=\s*([^\s>]*)/is', $str, $matches, PREG_SET_ORDER);
+			preg_match_all('/(?<!\w)('.implode('|', $evil_attributes).')\s*=\s*([^\s>]*)/is', $str, $matches, PREG_SET_ORDER);
 
 			foreach ($matches as $attr)
 			{