---
id: CVE-2025-1931
title: >-
  It was possible to cause a use-after-free in the content process side of a
  WebTransport connection, leading to a potentially exploitable crash
summary: >-
  It was possible to cause a use-after-free in the content process side of a
  WebTransport connection, leading to a potentially exploitable crash. This
  vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8,
  Thunderbi…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-416
vendor: mozilla
product: firefox
affected:
  - firefox < 115.21.0
  - firefox < 136.0
  - 'firefox >= 116.0, < 128.8.0'
  - thunderbird < 128.8.0
  - 'thunderbird >= 129.0, < 136.0'
patched:
  - firefox 128.8.0
  - thunderbird 136.0
published: '2025-03-04'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T19:10:01.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-1931'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1944126'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-14/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-15/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-16/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-17/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-18/'
    label: security@mozilla.org
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00538
epssPercentile: 0.43189
ingestedAt: '2026-09-30T19:21:07.227Z'
---

## Overview

It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

## Affected

- `firefox < 115.21.0`
- `firefox < 136.0`
- `firefox >= 116.0, < 128.8.0`
- `thunderbird < 128.8.0`
- `thunderbird >= 129.0, < 136.0`

## Remediation

Upgrade past the affected range:

- `firefox 128.8.0`
- `thunderbird 136.0`