An earlier fix for an Inter-process Communication (IPC) vulnerability, CVE-2011-3079, added authentication to communication between IPC endpoints and server parents during IPC process creation. This authentication is insufficient for channels created after the IPC process is started, leading to the authentication not being correctly applied to later channels. This could allow for a sandbox escape through IPC channels due to lack of message validation in the listener process. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.

The Inter-process Communication (IPC) implementation in Google Chrome before 18.0.1025.168, as used in Mozilla Firefox before 38.0 and other products, does not properly validate messages, which has unspecified impact and attack vectors.