The nsGfxScrollFrameInner::IsLTR function in Mozilla Firefox before 24.0, Firefox ESR 17.x before 17.0.9, Thunderbird before 24.0, Thunderbird ESR 17.x before 17.0.9, and SeaMonkey before 2.21 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to improperly establishing parent-child relationships of range-request nodes.