The browser engine in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, Thunderbird before 6, and possibly other products does not properly implement JavaScript, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14303
https://bugzilla.mozilla.org/show_bug.cgi?id=655660
http://www.mozilla.org/security/announce/2011/mfsa2011-33.html
http://www.mozilla.org/security/announce/2011/mfsa2011-31.html
http://www.mozilla.org/security/announce/2011/mfsa2011-29.html
http://secunia.com/advisories/49055
http://lists.opensuse.org/opensuse-security-announce/2011-08/msg00023.html