Use-after-free in Mozilla products - CVE-2026-124889
Published: November 10, 2026
Vulnerability identifier: #VU164533
CSH Severity: High
CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-124889
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service and potentially execute arbitrary code.
The vulnerability exists due to use-after-free in the CSS Parsing and Computation component when processing stylesheets. A remote attacker can supply crafted CSS that triggers access to freed memory to crash the browser or potentially execute arbitrary code.
Affected software
Firefox ESR
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
How to mitigate CVE-2026-124889
Install security update from vendor's website.
Firefox ESR - update to 153.7.0
Firefox for Android - update to 160.0
Mozilla Firefox - update to 160.0
Firefox for Android - update to 160.0
Mozilla Firefox - update to 160.0