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Vulnerability record · CVE-2025-14321 · published 9 December 2025

CVE-2025-14321: Mozilla firefox use after free vulnerability

Mozilla · Firefox

Use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

9.8 CVSS 3.1 Critical EPSS 0.60% · top 53.7% CWE-416 · Use after free
9.8CVSS 3.1 base score
0.60%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

Description

Use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.mozilla.org/show_bug.cgi?id=1992760 Issue TrackingPermissions Required
https://www.mozilla.org/security/advisories/mfsa2025-92/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-94/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-95/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-96/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-14321), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.