source: https://www.securityfocus.com/bid/39870/info

CF Image Hosting Script is prone to an arbitrary-file-upload vulnerability because it fails to properly sanitize user-supplied input.

An attacker can exploit this vulnerability to upload arbitrary code and run it in the context of the webserver process. This may facilitate unauthorized access or privilege escalation; other attacks are also possible.

CF Image Hosting Script 1.1 is vulnerable; other versions may also be affected. 

http://www.example.com/upload.php