The nsLocation::CheckURL function in Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, Thunderbird before 15.0, Thunderbird ESR 10.x before 10.0.7, and SeaMonkey before 2.12 does not properly follow the security model of the location object, which allows remote attackers to bypass intended content-loading restrictions or possibly have unspecified other impact via vectors involving chrome code.