source: https://www.securityfocus.com/bid/15959/info

Marwel is prone to an SQL injection vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input before using it in an SQL query.

Successful exploitation could result in a compromise of the application, disclosure or modification of data, or may permit an attacker to exploit vulnerabilities in the underlying database implementation.

Version 2.7 and prior are vulnerable; other versions may also be affected.

http://www.example.com/index.php?show=[SQL]