Improper access control in Mozilla Firefox and Firefox for Android - CVE-2026-16388
Published: July 22, 2026
Vulnerability identifier: #VU139008
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-16388
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
Detailed vulnerability description
The vulnerability allows a remote attacker to escape the sandbox.
The vulnerability exists due to improper access control in the DOM: Networking component when handling network operations. A remote attacker can trigger crafted network behavior to escape the sandbox.
How to mitigate CVE-2026-16388
Install security update from vendor's website.