source: https://www.securityfocus.com/bid/16793/info

NOCC Webmail is prone to multiple input-validation vulnerabilities. These issues are due to a failure in the application to properly sanitize user-supplied input.

An attacker can exploit these issues to inject arbitrary PHP code and execute it in the context of the vulnerable webserver. An attacker can also exploit these issues to execute arbitrary HTML or script code in the browser of a victim user in the context of the webserver process. This may facilitate the theft of cookie-based authentication credentials; other attacks are also possible.

http://www.example.com/[path]/html/error.php?html_error_occurred=<script>alert(document.cookie)</script>