Improper privilege management in Mozilla products - CVE-2026-16396
Published: July 21, 2026
Vulnerability identifier: #VU138991
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-16396
CWE-ID: CWE-269
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Firefox ESR
Mozilla Firefox
Firefox for Android
Firefox ESR
Mozilla Firefox
Firefox for Android
Detailed vulnerability description
The vulnerability allows a remote user to escalate privileges.
The vulnerability exists due to improper access control in WebExtensions when using extension functionality. A remote user can abuse extension functionality to escalate privileges.
Exploitation requires the use of WebExtensions.
How to mitigate CVE-2026-16396
Install security update from vendor's website.