source: https://www.securityfocus.com/bid/22143/info

SMF is prone to an HTML-injection vulnerability because it fails to properly sanitize user-supplied input before using it in dynamically generated content.

Attacker-supplied HTML and script code would execute in the context of the affected website, potentially allowing an attacker to steal cookie-based authentication credentials or to control how the site is rendered to the user; other attacks are also possible.

NOTE: To trigger this vulnerability, the attacker must log in with a valid account.

http://www.example.com/smf/index.php?action=pm;sa=send