source: https://www.securityfocus.com/bid/13097/info

Invision Power Board is reported prone to an SQL injection vulnerability. Due to improper filtering of user-supplied data, attackers may pass SQL statements to the underlying database through the 'st' parameter.

Invision Power Board 1.3.1 and prior versions are affected by this issue. 

http://www.example.com/forums/index.php?act=Members&max_results=30&filter=1&sort_order=asc&sort_key=name&st=SQL_INJECTION