Mozilla Firefox before 31.0 and Thunderbird before 31.0 do not properly implement the sandbox attribute of the IFRAME element, which allows remote attackers to bypass intended restrictions on same-origin content via a crafted web site in conjunction with a redirect.
https://security.gentoo.org/glsa/201504-01
https://bugzilla.mozilla.org/show_bug.cgi?id=985135
http://www.securitytracker.com/id/1030620
http://www.securitytracker.com/id/1030619
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2014/mfsa2014-66.html