---
id: CVE-2025-14321
title: 'Use-after-free in the WebRTC: Signaling component'
summary: >-
  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.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
  - CWE-416
vendor: mozilla
product: firefox
affected:
  - firefox < 140.6.0
  - firefox < 146.0
  - thunderbird < 140.6.0
  - thunderbird < 146.0
patched:
  - firefox 146.0
  - thunderbird 146.0
published: '2025-12-09'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T17:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-14321'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1992760'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-92/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-94/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-95/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-96/'
    label: security@mozilla.org
tags:
  - nvd
  - exploit-available
epss: 0.00596
epssPercentile: 0.46471
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/h3raklez/CVE-2025-14321'
  checkedAt: '2026-09-30T17:13:56.195Z'
exploitAvailable: true
ingestedAt: '2026-09-30T17:13:20.753Z'
---

## Overview

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

- `firefox < 140.6.0`
- `firefox < 146.0`
- `thunderbird < 140.6.0`
- `thunderbird < 146.0`

## Remediation

Upgrade past the affected range:

- `firefox 146.0`
- `thunderbird 146.0`