source: http://www.securityfocus.com/bid/15502/info

PHP-Fusion is prone to SQL injection vulnerabilities in multiple PHP scripts. These issues are 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. 

/forum/viewforum.php?forum_id=4&lastvisited='[SQL injection]

http://www.example.com/forum/viewforum.php?forum_id=1&lastvisited='