Unrestricted file upload vulnerability in usercp.php in MetaForum 0.513 Beta restricts file types based on the MIME type in the Content-type HTTP header, which allows remote attackers to upload and execute arbitrary scripts via an image MIME type with a filename containing an executable extension such as .php.
https://www.exploit-db.com/exploits/3516
https://exchange.xforce.ibmcloud.com/vulnerabilities/33097
http://www.securityfocus.com/bid/23032
http://www.securityfocus.com/archive/1/463178/100/0/threaded