CVE-2026-6776

Vulnerability

CVE-2026-6776 is an incorrect boundary conditions vulnerability in the WebRTC: Networking component of Firefox and Thunderbird. The flaw arises from improper handling of memory boundaries during WebRTC network operations, which can lead to memory corruption [1][2].

Exploitation

An attacker could exploit this vulnerability by crafting malicious WebRTC traffic that triggers the boundary condition error. In Thunderbird, scripting is disabled when reading mail, so exploitation through email is not possible; however, in browser or browser-like contexts (e.g., Firefox), the vulnerability is potentially exploitable without authentication if the victim visits a malicious page or receives crafted WebRTC data [1][3].

Impact

Successful exploitation could allow an attacker to corrupt memory, potentially leading to arbitrary code execution or a denial of service. The CVSS v3 score of 7.8 (High) reflects the serious nature of this memory safety issue [1][2].

Mitigation

Mozilla has fixed this vulnerability in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. Users should update to these versions or later to mitigate the risk [1][2][3][4].