Use-after-free in Mozilla products - CVE-2026-124863
Published: November 10, 2026
Vulnerability identifier: #VU164498
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-2026-124863
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 DOM: HTML Parser component when parsing HTML content. A remote attacker can supply crafted HTML that triggers access to freed memory to crash the browser process or potentially execute arbitrary code.
Affected software
Firefox for Android
Mozilla Firefox
Firefox ESR
Mozilla Firefox
Firefox ESR
How to mitigate CVE-2026-124863
Install security update from vendor's website.
Firefox for Android - update to 160.0
Mozilla Firefox - update to 160.0
Firefox ESR - addressed in versions 115.45.0, 153.7.0
Mozilla Firefox - update to 160.0
Firefox ESR - addressed in versions 115.45.0, 153.7.0