Privilege Escalation in Mozilla Firefox and ESR WebExtensions

CVE-2026-16396

What is CVE-2026-16396?

A privilege escalation vulnerability exists in the WebExtensions architecture of Mozilla Firefox and its Extended Support Release (ESR) version. This flaw could allow attackers to gain elevated privileges within the browser environment, potentially leading to unauthorized access or control over browser functionalities. The vulnerability has been addressed in the latest versions of Firefox 153 and Firefox ESR 140.13, emphasizing the importance of keeping browser software up-to-date to safeguard against such security threats.

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