Use-after-free vulnerability in the mozilla::dom::indexedDB::IDBKeyRange::cycleCollection::Trace function in Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allows remote attackers to execute arbitrary code via vectors related to crafted IndexedDB data.