CVE-2026-6768 describes a mitigation bypass vulnerability in the Networking: Cookies component of Mozilla Firefox. This flaw could allow bypassing security mitigations related to cookie handling, potentially impacting confidentiality, integrity, and availability. It was fixed in Firefox 150 and Thunderbird 150 as part of a comprehensive security update addressing multiple vulnerabilities, including memory safety bugs and privilege escalations. The CVSS 3.1 base score is 9.8, reflecting network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability.

The vulnerability could allow an attacker to bypass mitigation controls related to cookie handling in Firefox, potentially leading to unauthorized access or manipulation of cookie data. Given the critical CVSS score and the nature of the issue, successful exploitation could result in significant compromise of user data and browser security. However, no known exploits in the wild have been reported. The fix is included in Firefox 150 and Thunderbird 150, mitigating the risk for users who have updated.

Mozilla has released official fixes for this vulnerability in Firefox 150 and Thunderbird 150. Users and administrators should update to these versions or later to remediate the issue. Since this is a client-side software vulnerability, applying the official update is the primary and recommended mitigation. There are no vendor indications that additional mitigations or workarounds are necessary.