CVE 2012-3986
Mozilla Firefox before 16.0, Firefox ESR 10.x before 10.0.8, Thunderbird before 16.0, Thunderbird ESR 10.x before 10.0.8, and SeaMonkey before 2.13 do not properly restrict calls to DOMWindowUtils (aka nsDOMWindowUtils) methods, which allows remote attackers to bypass intended access restrictions via crafted JavaScript code.
See the 
CVE page on Mitre.org
for more details.
