Mozilla » Seamonkey : Security Vulnerabilities, CVEs, Published In November 2007 (XSS)

The jar protocol handler in Mozilla Firefox before 2.0.0.10 and SeaMonkey before 1.1.7 retrieves the inner URL regardless of its MIME type, and considers HTML documents within a jar archive to have the same origin as the inner URL, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a jar: URI.