Use-after-free vulnerability in the WebRTC implementation in Mozilla Firefox before 35.0, Firefox ESR 31.x before 31.4, and SeaMonkey before 2.32 allows remote attackers to execute arbitrary code via crafted track data.

Mozilla Firefox before 35.0, Firefox ESR 31.x before 31.4, Thunderbird before 31.4, and SeaMonkey before 2.32 do not properly interpret Set-Cookie headers within responses that have a 407 (aka Proxy Authentication Required) status code, which allows remote HTTP proxy servers to conduct session fixation attacks by providing a cookie name that corresponds to the session cookie of the origin server.