Use-after-free in Mozilla products - CVE-2026-117866
Published: October 27, 2026
Vulnerability identifier: #VU158066
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-2026-117866
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to escalate privileges.
The vulnerability exists due to use-after-free in the Canvas2D graphics component when processing canvas content. A remote attacker can supply crafted content to trigger access to freed memory and escalate privileges.
Affected software
Mozilla Firefox
Firefox ESR
Firefox for Android
Firefox ESR
Firefox for Android
How to mitigate CVE-2026-117866
Install security update from vendor's website.
Mozilla Firefox - update to 159.0
Firefox for Android - update to 159.0
Firefox ESR - addressed in versions 115.44.0, 153.6.0
Firefox for Android - update to 159.0
Firefox ESR - addressed in versions 115.44.0, 153.6.0