Cross-site scripting (XSS) vulnerability in W3C Jigsaw Proxy Server before 2.2.1 allows remote attackers to execute arbitrary script via a URL that contains a reference to a nonexistent host followed by the script, which is included in the resulting error message.
http://www.w3.org/Jigsaw/RelNotes.html#2.2.1
http://www.securityfocus.com/bid/5506
http://www.iss.net/security_center/static/9914.php
http://archives.neohapsis.com/archives/bugtraq/2002-08/0190.html