source: http://www.securityfocus.com/bid/14636/info

PostNuke is prone to an SQL injection vulnerability. This issue is due to a lack of sufficient sanitization of user-supplied input.

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. 

http://www.example.com/[DIR]/index.php?name=Downloads&req=viewdownload&cid=1&show=[SQL%20INJECTION]