---
id: CVE-2025-6432
title: >-
  When Multi-Account Containers was enabled, DNS requests could have bypassed a
  SOCKS proxy when the domain name was invalid or the SOCKS proxy was not
  responding
summary: >-
  When Multi-Account Containers was enabled, DNS requests could have bypassed a
  SOCKS proxy when the domain name was invalid or the SOCKS proxy was not
  responding. This vulnerability was fixed in Firefox 140 and Thunderbird 140.
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L'
cwe:
  - CWE-200
vendor: mozilla
product: firefox
affected:
  - firefox < 140.0
patched:
  - firefox 140.0
published: '2025-06-24'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-6432'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1943804'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-51/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-54/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.0035
epssPercentile: 0.26253
ingestedAt: '2026-09-30T18:17:24.445Z'
---

## Overview

When Multi-Account Containers was enabled, DNS requests could have bypassed a SOCKS proxy when the domain name was invalid or the SOCKS proxy was not responding. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

## Affected

- `firefox < 140.0`

## Remediation

Upgrade past the affected range:

- `firefox 140.0`