Mozilla Firefox 4.x through 13.0 and Firefox ESR 10.x before 10.0.6 do not properly establish the security context of a feed: URL, which allows remote attackers to bypass unspecified cross-site scripting (XSS) protection mechanisms via a feed:javascript: URL.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.