PHP-Nuke 7.4 has a cross site scripting flaw that allows an attacker the ability to delete any admin account. It is an old bug that has a patch that can be bypassed if the data is sent via a POST instead of a GET.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/34270/codelabs-02.txt
Source: https://packetstormsecurity.com/files/34270/CODEBUG-Labs-Security-Advisory-2.html