Issued at: 2026-09-27
Updated at: 2026-09-27
Advisory content derived from Red Hat RHSA-2026:67129, © Red Hat, Inc., used under CC BY 4.0, with modifications.
Synopsis
Important: firefox security update
Description
Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.
Security Fix(es):
* firefox: thunderbird: Privilege escalation in the DOM: Workers component (CVE-2026-16365)
* firefox: thunderbird: Sandbox escape in the Remote Settings Client component (CVE-2026-75874)
* firefox: Sandbox escape due to use-after-free in the DOM: Security component (CVE-2026-84121)
* firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40 (CVE-2026-84145)
* firefox: Sandbox escape due to use-after-free in the DOM: Navigation component (CVE-2026-84119)
* firefox: Use-after-free in the Audio/Video component (CVE-2026-84120)
* firefox: Privilege escalation due to invalid pointer in the Graphics component (CVE-2026-84131)
* firefox: Use-after-free in the DOM: Core & HTML component (CVE-2026-84124)
* firefox: Use-after-free in the Audio/Video component (CVE-2026-84122)
* firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2 and Firefox ESR 140.15 (CVE-2026-84143)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.