source: https://www.securityfocus.com/bid/10861/info

PHP-Nuke is reported prone to an access control bypass vulnerability.

Reports indicate that a PHP-Nuke superuser may bypass access controls and privilege restrictions, to delete the PHP-Nuke "God Admin" account. This may be accomplished by making a specially crafted request for the "admin.php" script.

http://www.example.com/phpnuke/admin.php?op=deladmin2&del_aid=dudul

Where "dudul" is the name of the target "God Admin" account.