source: https://www.securityfocus.com/bid/21497/info

cPanel BoxTrapper is prone to a cross-site scripting vulnerability because the application fails to properly sanitize user-supplied input. 

An attacker may leverage this issue to have arbitrary script code execute in the browser of an unsuspecting user. This may help the attacker steal cookie-based authentication credentials and launch other attacks.

cPanel 11 is vulnerable to this issue; other versions may also be affected.

http://www.example.com/frontend/xtest/mail/manage.html?account=