source: http://www.securityfocus.com/bid/1777/info

The $page variable in Hassan Consulting Shopping Cart does not properly check for insecure relative paths such as the double dot "..". Therefore, requesting the following URL will display the specified file:

http://target/cgi-bin/shop.cgi/page=../../../path/filename.ext

Successful exploitation could lead to a remote intruder gaining read access to any known file.