Integer overflow in Mozilla products - CVE-2026-109723
Published: October 16, 2026
Vulnerability identifier: #VU156018
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-2026-109723
CWE-ID: CWE-190
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to trigger incorrect arithmetic results that may cause a denial of service or memory corruption.
The vulnerability exists due to integer overflow in the Layout: Text and Fonts component when performing text and font layout calculations. A remote attacker can supply crafted content that causes a calculation to exceed its integer range to produce incorrect values that may disrupt processing or memory handling.
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-2026-109723
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