Use-after-free in Mozilla products - CVE-2026-109765
Published: October 16, 2026
Vulnerability identifier: #VU156041
CSH Severity: Medium
CVSS v4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-109765
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 associated with a race condition in the Graphics: Text component when handling concurrent text graphics operations. A remote attacker can trigger affected operations with conflicting timing to access freed memory, causing a crash and potentially arbitrary code execution.
Affected software
Firefox ESR
Mozilla Firefox
Firefox for Android
Debian Linux
firefox-esr (Debian package)
Mozilla Firefox
Firefox for Android
Debian Linux
firefox-esr (Debian package)
How to mitigate CVE-2026-109765
Install security update from vendor's website.
Firefox ESR - update to 153.5.0
Firefox for Android - update to 158.0
Mozilla Firefox - update to 158.0
firefox-esr (Debian package) - update to 153.5.0esr-1~deb13u1
Firefox for Android - update to 158.0
Mozilla Firefox - update to 158.0
firefox-esr (Debian package) - update to 153.5.0esr-1~deb13u1