source: https://www.securityfocus.com/bid/2109/info

It is possible for a remote user to gain read access to various files that reside within the EZShopper directory. By requesting a specially crafted URL utilizing loadpage.cgi' application with a '/' appended, EZShopper will disclose the contents within the EZShopper directory. As a result, it is possible for an attacker to navigate into its subdirectories and view any file.

It is also reported that this same CGI application allows directory traversal sequences to be utilized to retrieve the contents of arbitrary Web server accessible files.

Successful exploitation of this vulnerability could lead to the disclosure of sensitive information and possibly assist in further attacks against the victim. 

EZshopper v3.0:
http://www.example.com/cgi-bin/ezshopper3/loadpage.cgi?user_id=id&file=/

EZshopper v2.0:
http://www.example.com/cgi-bin/ezshopper2/loadpage.cgi?id+/

Zero X <Zero_X@excluded.org> provided the following example:
http://www.example.com/cgi-bin/loadpage.cgi?user_id=id&file=.|./.|./.|./.|./.|./etc/passwd%00.html