source: http://www.securityfocus.com/bid/12720/info

D-Forum is reportedly affected by a cross-site scripting vulnerability. This issue is due to the application failing to properly sanitize user-supplied input.

As a result of this vulnerability, it is possible for a remote attacker to create a malicious link containing script code that will be executed in the browser of an unsuspecting user when followed. This may facilitate the theft of cookie-based authentication credentials as well as other attacks.

This vulnerability is reported to affect D-Forum 1.11; earlier versions may also be affected. 

http://www.example.com/dforum/nav.php3?page=[code]