Input validation error in Mozilla Firefox and Firefox for Android - CVE-2026-8391
Published: May 12, 2026
Vulnerability identifier: #VU131171
CSH Severity: High
CVSS v4.0: 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/E:U/U:Amber
CVE-ID: CVE-2026-8391
CWE-ID: CWE-20
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 compromise the affected system.
The vulnerability exists due to an unspecified issue in the JavaScript Engine component. A remote attacker can trick the victim into visiting a specially crafted website and execute arbitrary code on the system.
How to mitigate CVE-2026-8391
Install updates from vendor's website.