Use-after-free vulnerability in 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 might allow user-assisted remote attackers to execute arbitrary code via vectors involving use of mozRequestFullScreen to enter full-screen mode and use of the history.back method for backwards history navigation.