source: https://www.securityfocus.com/bid/16604/info

XMB Forum is prone to multiple input-validation vulnerabilities, including cross-site scripting and SQL-injection issues, because the application fails to properly sanitize user-supplied input.

Successful exploits of these vulnerabilities could allow an attacker to compromise the application, access or modify data, steal cookie-based authentication credentials, or exploit vulnerabilities in the underlying database. Other attacks are also possible.

http://www.example.com/u2u.php?action=send&username=%22%3E%3Ciframe%3E