What is CVE-2025-14330?

CVE-2025-14330 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2025-12-09.

How severe is CVE-2025-14330?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2025-14330

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

Vulnerability class: Buffer Overflow

Published 2025-12-09 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.005 (40.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 40.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Mozilla Firefox — versions 140.6, 146
Mozilla Thunderbird — versions 140.6, 146

Weakness classification (CWE)

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
www.mozilla.org/security/advisories/mfsa2025-92/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2025-94/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2025-95/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2025-96/ (Vendor Advisory)

Frequently asked questions

What is CVE-2025-14330?: CVE-2025-14330 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2025-12-09.
How severe is CVE-2025-14330?: Critical severity. CVSS v3 base score is 9.8 out of 10.