The Chrome Object Wrapper (COW) implementation 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 does not properly interact with failures of InstallTrigger methods, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted web site, related to an "XrayWrapper pollution" issue.