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 JSAPI access to the GetProperty function, which allows remote attackers to bypass the Same Origin Policy and possibly have unspecified other impact via a crafted web site.