Protection mechanism failure in Firefox for Android and Mozilla Firefox - CVE-2026-16394
Published: July 22, 2026
Vulnerability identifier: #VU139012
CSH Severity: Medium
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-16394
CWE-ID: CWE-693
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass a security mitigation.
The vulnerability exists due to improper access control in the DOM: Security component when handling security checks. A remote attacker can trigger crafted behavior to bypass a security mitigation.
Affected software
Firefox for Android
Mozilla Firefox
Mozilla Thunderbird
Mozilla Firefox
Mozilla Thunderbird
How to mitigate CVE-2026-16394
Install security update from vendor's website.
Firefox for Android - update to 153.0
Mozilla Firefox - update to 153.0
Mozilla Thunderbird - update to 153.0
Mozilla Firefox - update to 153.0
Mozilla Thunderbird - update to 153.0