Vulnerability in Mozilla Firefox
CVE-2026-8091
Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, Thunderbird 140.10.1, and Firefox ESR 115.35.2.
EPSS: 0.000 (6.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Mozilla Firefox — versions 140.10.2, 140.10.1, 150
- Mozilla Thunderbird — versions 140.10.1, 150
Weakness classification (CWE)
References
- security@mozilla.org (Permissions Required)
- security@mozilla.org
- security@mozilla.org (Vendor Advisory)
- 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-2026-8091?
- CVE-2026-8091 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 9.8/10. Published 2026-05-07.
- How severe is CVE-2026-8091?
- Critical severity. CVSS v3 base score is 9.8 out of 10.