Cross-site scripting (XSS) vulnerability in misc.php in MyBB (aka MyBulletinBoard) before 1.6.12 allows remote attackers to inject arbitrary web script or HTML via the editor parameter in a smilie list popup.
http://www.securityfocus.com/bid/64570
http://secunia.com/advisories/55945
http://blog.mybb.com/2013/12/16/mybb-1-6-12-released-security-maintenance-release