Vulnerability in Mozilla Firefox
CVE-2026-6763
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
EPSS: 0.002 (9.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Mozilla Firefox — versions 140.10, 150
- Mozilla Thunderbird — versions 140.10, 150
Weakness classification (CWE)
References
- security@mozilla.org (Permissions Required)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-6763?
- CVE-2026-6763 is a medium-severity vulnerability in Mozilla Firefox, classified under Protection Mechanism Failure. CVSS score: 6.5/10. Published 2026-04-21.
- How severe is CVE-2026-6763?
- Medium severity. CVSS v3 base score is 6.5 out of 10.