Use After Free in Mozilla Firefox
CVE-2026-8947
Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Vulnerability class: Use-After-Free
EPSS: 0.001 (20.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
Affected products
- Mozilla Firefox — versions 115.36, 140.11, 151
- Mozilla Thunderbird — versions 140.11, 151
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)
- security@mozilla.org (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-8947?
- CVE-2026-8947 is a high-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 7.3/10. Published 2026-05-19.
- How severe is CVE-2026-8947?
- High severity. CVSS v3 base score is 7.3 out of 10.