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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00086.

Exploitation none

Automatable yes

Technical Impact total

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Mozilla Firefox affected
Version Status Constraints
140.6 unaffected ≤ 140.*
146 unaffected ≤ *
Mozilla Thunderbird affected
Version Status Constraints
140.6 unaffected ≤ 140.*
146 unaffected ≤ *

Configuration 1 [-]

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

No data.

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Vendors Products
Mozilla Subscribe
Firefox Subscribe
Firefox Esr Subscribe

Project Subscriptions

Vendors Products
Mozilla Subscribe
Firefox Subscribe
Firefox Esr Subscribe
Thunderbird Subscribe
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4401-1 firefox-esr security update
Debian DLA Debian DLA DLA-4405-1 thunderbird security update
Debian DSA Debian DSA DSA-6078-1 firefox-esr security update
Debian DSA Debian DSA DSA-6081-1 thunderbird security update
Ubuntu USN Ubuntu USN USN-7991-1 Thunderbird vulnerabilities
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=1992760 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-14321 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-14321 cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-92/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-94/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-94/#CVE-2025-14321 cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-95/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-96/ cve-icon cve-icon
History

Mon, 13 Apr 2026 15:00:00 +0000

Type Values Removed Values Added
Description Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6. 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.

Thu, 11 Dec 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Thu, 11 Dec 2025 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
Weaknesses CWE-416
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

 cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Wed, 10 Dec 2025 18:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Mozilla firefox Esr
Vendors & Products Mozilla
Mozilla firefox
Mozilla firefox Esr

Wed, 10 Dec 2025 14:45:00 +0000

Type Values Removed Values Added
Description Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146 and Firefox ESR < 140.6. Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.
References

Wed, 10 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

threat_severity

Important

Tue, 09 Dec 2025 13:45:00 +0000

Type Values Removed Values Added
Description Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146 and Firefox ESR < 140.6.
Title Use-after-free in the WebRTC: Signaling component
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-04-13T14:25:27.309Z

Reserved: 2025-12-09T13:37:53.205Z

Link: CVE-2025-14321

cve-icon Vulnrichment

Updated: 2025-12-11T19:37:33.982Z

cve-icon NVD

Status : Modified

Published: 2025-12-09T16:17:39.410

Modified: 2026-04-13T15:16:44.820

Link: CVE-2025-14321

cve-icon Redhat

Severity : Important

Publid Date: 2025-12-09T13:37:53Z

Links: CVE-2025-14321 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-12-10T17:51:14Z

Weaknesses