source: http://www.securityfocus.com/bid/14635/info
 
PostNuke is prone to multiple cross-site scripting vulnerabilities. These issues are due to a failure of the application to properly sanitize user-supplied input.
 
This can lead to theft of cookie-based authentication credentials, as well as other types of attacks. 

http://www.example.com/PostNuke-0.760-RC4b/html/user.php?op=edituser&htmltext=<h1>xss