Use-after-free vulnerability in the ListenerManager implementation in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and 17.x before 17.0.2, Thunderbird before 17.0.2, Thunderbird ESR 10.x before 10.0.12 and 17.x before 17.0.2, and SeaMonkey before 2.15 allows remote attackers to execute arbitrary code via vectors involving the triggering of garbage collection after memory allocation for listener objects.