XSS in Null HTTPd

["Matthew Murphy" <mattmurphy () kc rr com>]

Null HTTPd is a simple HTTP server that runs on Win32/Unix systems.  It is
quite basic, but offers good CGI support.  A vulnerability in Null HTTPd may
allow cross-site scripting via a 404 page:

http://localhost/a?x=<SCRIPT>alert(document.URL)</SCRIPT>

You have to place this in the query string so that it doesn't get the
typical "%xx..." urlencode treatment from the browser.  If the code is
encoded in any way, it prevents the vulnerability from working.

"The reason the mainstream is thought
of as a stream is because it is
so shallow."
                     - Author Unknown