Mozilla Firefox before 37.0 relies on docshell type information instead of page principal information for Window.webidl access control, which might allow remote attackers to execute arbitrary JavaScript code with chrome privileges via certain content navigation that leverages the reachability of a privileged window with an unintended persistence of access to restricted internal methods.
https://www.exploit-db.com/exploits/37958/
https://security.gentoo.org/glsa/201512-10
https://bugzilla.mozilla.org/show_bug.cgi?id=1124898
http://www.ubuntu.com/usn/USN-2550-1
http://www.securitytracker.com/id/1031996
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2015/mfsa2015-42.html
http://lists.opensuse.org/opensuse-security-announce/2015-04/msg00003.html