Directory traversal vulnerability in mainfile.php in PHP-Nuke 8.0 and earlier allows remote attackers to read arbitrary files via a .. (dot dot) in the lang parameter.
http://www.securityfocus.com/bid/22909
http://www.securityfocus.com/archive/1/462588/100/0/threaded
http://www.securityfocus.com/archive/1/462443/100/0/threaded