JIT Miscompilation Vulnerability in Mozilla Firefox and ESR
CVE-2026-124939

Currently unrated

Key Information:

Vendor: Mozilla
Status: Firefox
Vendor: CVE Published:; 10 November 2026

What is CVE-2026-124939?

A JIT miscompilation vulnerability has been identified in the JavaScript Engine component of Mozilla Firefox. This flaw may allow for unexpected behavior in the execution of JavaScript code, potentially leading to security concerns. Mozilla has addressed this issue in the latest updates, including Firefox version 160 and Firefox ESR version 153.7, ensuring that users benefit from a more robust and secure browsing experience.

Affected Version(s)

Firefox 153.7

Firefox 160

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2076663

https://www.mozilla.org/security/advisories/mfsa2026-125/

https://www.mozilla.org/security/advisories/mfsa2026-127/

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Nov 10, 2026
Vulnerability Reserved
Nov 9, 2026

Credit

SecBuddyN, Tencent KeenLab (CodeBuddy Security)

CVE-2026-124939 Data

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