XSS Challenge #4

Welcome to my fourth XSS challenge!

The following XSS challenge discuss an issue on PHP. It is based on a patch that can be used to perform a XSS attack under certain scenarios (More details would make it extremely easy to solve).

This challenge difficulty can be count as easy comparing to other challenges in my opinion.

The challenge's would teach you few techniques about CRLF injection, XSS, etc..

This challenge's goal is to execute an alert() on this page, by following the rules.