diff --git a/phpBB/includes/message_parser.php b/phpBB/includes/message_parser.php
index 138c7f48bf..ab0ee59943 100644
--- a/phpBB/includes/message_parser.php
+++ b/phpBB/includes/message_parser.php
@@ -523,10 +523,10 @@ class bbcode_firstpass extends bbcode
 					$out .= array_pop($list_end_tags) . ']';
 					$tok = '[';
 				}
-				else if (preg_match('#list(=[0-9a-z])?#i', $buffer, $m))
+				else if (preg_match('#^list(=[0-9a-z])?$#i', $buffer, $m))
 				{
 					// sub-list, add a closing tag
-					if (empty($m[1]) || preg_match('/^(disc|square|circle)$/i', $m[1]))
+					if (empty($m[1]) || preg_match('/^(?:disc|square|circle)$/i', $m[1]))
 					{
 						array_push($list_end_tags, '/list:u:' . $this->bbcode_uid);
 					}