From NukeCops: "Recently a security hole was announced in reference to an admin.php exploit where anyone can obtain PHP-Nuke administrator access."
I have added a few lines to the suggested fix to make it a bit easier to know which function call to use. Please see this post for the fix.
Admin Note: I have updated the v6.9 download pack, from this site, as of 10/14/2003 17:25 to include this patch.