source: https://www.securityfocus.com/bid/36710/info

Snitz Forums 2000 is prone to a cross-site scripting vulnerability and an HTML-injection vulnerability because it fails to sufficiently sanitize user-supplied data.

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

Snitz Forums 2000 3.4.07 is vulnerable; other versions may also be affected. 

http://www.example.com/forum/pop_send_to_friend.asp?url=&lt;/textarea&gt;<img
src="http://www.google.it/intl/it_it/images/logo.gif" onLoad
="alert(document.cookie)">