Vulnerability Description
JIT miscompilation in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
CVSS Score
9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.9.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2013560Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-20/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-22/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
FAQ
What is CVE-2026-4702?
CVE-2026-4702 is a vulnerability with a CVSS score of 9.8 (CRITICAL). JIT miscompilation in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
How severe is CVE-2026-4702?
CVE-2026-4702 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-4702?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox.