SMF 1.1.1 is vulnerabil too. solution -> In file PersonalMessage.php change 1417 and 1418 lines adding htmlspecialchars() like this -> $_REQUEST['to'] = empty($_POST['to']) ? (empty($_GET['to']) ? '' : $_GET['to']) : htmlspecialchars(stripslashes($_POST['to'])); $_REQUEST['bcc'] = empty($_POST['bcc']) ? (empty($_GET['bcc']) ? '' : $_GET['bcc']) : htmlspecialchars(stripslashes($_POST['bcc']));