Flatnuke 3 (aka FlatnuX) allows remote attackers to obtain administrative access via a myforum%00 cookie.

Direct static code injection vulnerability in the download module in Flatnuke 3 allows remote authenticated administrators to inject arbitrary PHP code into a description.it.php file in a subdirectory of Download/ by saving a description and setting fneditmode to 1. NOTE: unauthenticated remote attackers can exploit this by leveraging a cookie manipulation issue.

Cross-site request forgery (CSRF) vulnerability in index.php in the File Manager module in Flatnuke 3 allows remote attackers to perform certain actions as administrators via requests containing the pathname in the dir parameter and the filename in the ffile parameter.

index.php in the File Manager module in Flatnuke 3 allows remote attackers to obtain sensitive information via an invalid argumentname parameter in a disc op action, which reveals the path in an error message.