Cross-site scripting (XSS) vulnerability in admin/modules/user/users.php in MyBB (aka MyBulletinBoard) 1.6.6 allows remote attackers to inject arbitrary web script or HTML via the conditions[usergroup][] parameter in a search action to admin/index.php.
https://exchange.xforce.ibmcloud.com/vulnerabilities/74397
http://packetstormsecurity.org/files/111238/MyBB-1.6.6-Cross-Site-Scripting-SQL-Injection.html