The cross-site request forgery (CSRF) protection in PHP-Nuke 8.0 and earlier does not ensure the SERVER superglobal is an array before validating the HTTP_REFERER, which allows remote attackers to conduct CSRF attacks.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2007-1514
http://www.wisec.it/ush/phpnukexss.html
http://www.ush.it/2007/03/09/php-nuke-wild-post-xss/
http://www.securityfocus.com/archive/1/462727/100/0/threaded
http://www.securityfocus.com/archive/1/462575/100/0/threaded
http://www.securityfocus.com/archive/1/462308/100/100/threaded