Fix #5331
diff --git a/system/helpers/url_helper.php b/system/helpers/url_helper.php
index f6fb7d9..489f2d4 100644
--- a/system/helpers/url_helper.php
+++ b/system/helpers/url_helper.php
@@ -393,7 +393,7 @@
 	function auto_link($str, $type = 'both', $popup = FALSE)
 	{
 		// Find and replace any URLs.
-		if ($type !== 'email' && preg_match_all('#(\w*://|www\.)[^\s()<>;]+\w/?#i', $str, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER))
+		if ($type !== 'email' && preg_match_all('#(\w*://|www\.)[a-z0-9]+(-+[a-z0-9]+)*(\.[a-z0-9]+(-+[a-z0-9]+)*)+(/([^\s()<>;]+\w)?/?)?#i', $str, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER))
 		{
 			// Set our target HTML if using popup links.
 			$target = ($popup) ? ' target="_blank"' : '';