Protection mechanism failure in Mozilla Firefox and Firefox for Android - CVE-2026-109746
Published: October 16, 2026
Vulnerability identifier: #VU156059
CSH Severity: Medium
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-109746
CWE-ID: CWE-693
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass browser security protections.
The vulnerability exists due to inadequate enforcement of security protections in the DOM: Security component when handling document security operations. A remote attacker can trigger operations that evade the affected protection to bypass its intended restrictions.
Affected software
Mozilla Firefox
Firefox for Android
Firefox for Android
How to mitigate CVE-2026-109746
Install security update from vendor's website.
Mozilla Firefox - update to 158.0
Firefox for Android - update to 158.0
Firefox for Android - update to 158.0