CVE-2025-14321
published 2025-12-09CVE-2025-14321: 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.
PriorityP352critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.52%
40.5th percentile
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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 146.0-1 (sid) | firefox 146.0-1 (sid) |
| debian | firefox-esr | < firefox 146.0-1 (sid) | firefox 146.0-1 (sid) |
| debian | thunderbird | < firefox 146.0-1 (sid) | firefox 146.0-1 (sid) |
| mozilla | firefox | < 140.6.0 | 140.6.0 |
| mozilla | firefox | < 146.0 | 146.0 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | < 140.6.0 | 140.6.0 |
| mozilla | thunderbird | < 146.0 | 146.0 |
| mozilla | thunderbird | >= 0 < 1:140.6.0esr-1~deb11u1 | 1:140.6.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.6.0esr-1~deb12u1 | 1:140.6.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.6.0esr-1~deb13u1 | 1:140.6.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.6.0esr-1 | 1:140.6.0esr-1 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
osv9.8CRITICAL
vendor_debian9.8CRITICAL
vendor_redhat9.8CRITICAL
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Ubuntu
Thunderbird vulnerabilities
vendor_ubuntu·2026-02-02
CVE-2025-8031 Thunderbird vulnerabilities
Title: Thunderbird vulnerabilities
Summary: Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass security restrictions, cross-site
tracing, or execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
vendor_redhat·2025-12-09·CVSS 9.8
CVE-2025-14321 [CRITICAL] firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: Use-after-free in the WebRTC: Signaling component.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: thunderbird (Red Hat Enterprise Linux
Debian
CVE-2025-14321: firefox - Use-after-free in the WebRTC: Signaling component. This vulnerability affects Fi...
vendor_debian·2025·CVSS 9.8
CVE-2025-14321 [CRITICAL] CVE-2025-14321: firefox - Use-after-free in the WebRTC: Signaling component. This vulnerability affects Fi...
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.
Scope: local
sid: resolved (fixed in 146.0-1)
Mozilla
Mozilla Foundation Security Advisory 2025-92: CVE-2025-14321
vendor_mozilla·CVSS 9.8
CVE-2025-14321 [CRITICAL] Mozilla Foundation Security Advisory 2025-92: CVE-2025-14321
Mozilla Foundation Security Advisory 2025-92
CVE: CVE-2025-14321
Product: Firefox
Impact: moderate
Fixed in: Firefox 146
Mozilla
Mozilla Foundation Security Advisory 2025-94: CVE-2025-14321
vendor_mozilla·CVSS 9.8
CVE-2025-14321 [CRITICAL] Mozilla Foundation Security Advisory 2025-94: CVE-2025-14321
Mozilla Foundation Security Advisory 2025-94
CVE: CVE-2025-14321
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 140.6
Mozilla
Mozilla Foundation Security Advisory 2025-96: CVE-2025-14321
vendor_mozilla·CVSS 9.8
CVE-2025-14321 [CRITICAL] Mozilla Foundation Security Advisory 2025-96: CVE-2025-14321
Mozilla Foundation Security Advisory 2025-96
CVE: CVE-2025-14321
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 140.6
Mozilla
Mozilla Foundation Security Advisory 2025-95: CVE-2025-14321
vendor_mozilla·CVSS 9.8
CVE-2025-14321 [CRITICAL] Mozilla Foundation Security Advisory 2025-95: CVE-2025-14321
Mozilla Foundation Security Advisory 2025-95
CVE: CVE-2025-14321
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 146
VulDB
Mozilla Firefox up to 145 WebRTC Signaling use after free (Nessus ID 278145 / WID-SEC-2025-2812)
vuldb·2026-06-12·CVSS 9.8
CVE-2025-14321 [CRITICAL] Mozilla Firefox up to 145 WebRTC Signaling use after free (Nessus ID 278145 / WID-SEC-2025-2812)
A vulnerability identified as critical has been detected in Mozilla Firefox up to 145. This issue affects some unknown processing of the component WebRTC Signaling Component. The manipulation leads to use after free.
This vulnerability is documented as CVE-2025-14321. The attack can be initiated remotely. There is not any exploit available.
You should upgrade the affected component.
GHSA
GHSA-g2fh-3663-3jf8: Use-after-free in the WebRTC: Signaling component
ghsa_unreviewed·2025-12-09
CVE-2025-14321 [CRITICAL] CWE-416 GHSA-g2fh-3663-3jf8: Use-after-free in the WebRTC: Signaling component
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146 and Firefox ESR < 140.6.
OSV
CVE-2025-14321: Use-after-free in the WebRTC: Signaling component
osv·2025-12-09·CVSS 9.8
CVE-2025-14321 [CRITICAL] CVE-2025-14321: Use-after-free in the WebRTC: Signaling component
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.
No detection rules found.
No public exploits indexed.
Wiz
CVE-2025-14321 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 9.8
CVE-2025-14321 [CRITICAL] CVE-2025-14321 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2025-14321 :
NixOS vulnerability analysis and mitigation
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.
Source : NVD
## 9.8
Score
Published December 9, 2025
Severity CRITICAL
CNA Score 9.8
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit Yes
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 20.6
Exploitation Probability (EPSS) 0.1
Affected packages and libraries
rhel10::firefox-flatpak.src
firefox
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Dec 12, 2025
AlmaLinux 9 Severity HIGH Has Fix Added at: Dec 12, 2025
Debian 11, 12, 13, 14 Severity CRITICAL Has Fix Added
Bugzilla
CVE-2025-14321 firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
bugzilla·2025-12-09·CVSS 9.8
CVE-2025-14321 [CRITICAL] CVE-2025-14321 firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
CVE-2025-14321 firefox: thunderbird: Use-after-free in the WebRTC: Signaling component
Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146 and Firefox ESR < 140.6.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2025:23035 https://access.redhat.com/errata/RHSA-2025:23035
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2025:23034 https://access.redhat.com/errata/RHSA-2025:23034
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2025:23128 https://access.redhat.com/errata/RHSA-2025:23128
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-20
2025-12-09
Published