CVE-2012-3989
Mozilla Firefox before 16.0, Thunderbird before 16.0, and SeaMonkey before 2.13 do not properly perform a cast of an unspecified variable during use of the instanceof operator on a JavaScript object, which allows remote attackers to execute arbitrary code or cause a denial of service (assertion failure) via a crafted web site.
Date published : 2012-10-10
http://www.mozilla.org/security/announce/2012/mfsa2012-80.html