Mozilla Firefox before 9.0, Thunderbird before 9.0, and SeaMonkey before 2.6 on Mac OS X do not properly handle certain DOM frame deletions by plugins, which allows remote attackers to cause a denial of service (incorrect pointer dereference and application crash) or possibly have unspecified other impact via a crafted web site.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14574
https://bugzilla.mozilla.org/show_bug.cgi?id=649079
http://www.securitytracker.com/id?1026447
http://www.securitytracker.com/id?1026446
http://www.securitytracker.com/id?1026445
http://www.mozilla.org/security/announce/2011/mfsa2011-57.html