Use After Free in Mozilla Firefox
CVE-2026-2804
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
Vulnerability class: Use-After-Free
EPSS: 0.003 (21.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
Affected products
- Mozilla Firefox — versions 148
- Mozilla Thunderbird — versions 148
Weakness classification (CWE)
References
- security@mozilla.org (Permissions Required)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-2804?
- CVE-2026-2804 is a medium-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 5.4/10. Published 2026-02-24.
- How severe is CVE-2026-2804?
- Medium severity. CVSS v3 base score is 5.4 out of 10.