Cross-site scripting (XSS) vulnerability in ZyXEL ZyWALL 100 allows remote attackers to inject arbitrary web script or HTML via the Referer header, which is not properly handled in a 404 Error page.
https://exchange.xforce.ibmcloud.com/vulnerabilities/42282
http://www.vupen.com/english/advisories/2008/1501/references
http://www.securitytracker.com/id?1020000
http://www.securityfocus.com/archive/1/491818/100/0/threaded