Cross-site scripting (XSS) vulnerability in attachment.php in MyBulletinBoard (MyBB) 1.1.7 and possibly other versions allows remote attackers to inject arbitrary web script or HTML via a GIF image that contains URL-encoded Javascript, which is rendered by Internet Explorer.
https://exchange.xforce.ibmcloud.com/vulnerabilities/28587
http://www.securityfocus.com/archive/1/444414/100/0/threaded
http://www.mybboard.com/archive.php?nid=18