---
id: CVE-2025-14331
title: Same-origin policy bypass in the Request Handling component
summary: >-
  Same-origin policy bypass in the Request Handling component. This
  vulnerability was fixed in Firefox 146, Firefox ESR 115.31, Firefox ESR 140.6,
  Thunderbird 146, and Thunderbird 140.6.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-346
  - CWE-346
vendor: mozilla
product: firefox
affected:
  - firefox < 115.31.0
  - firefox < 146.0
  - 'firefox >= 116.0, < 140.6.0'
  - thunderbird < 140.6.0
  - thunderbird < 146.0
patched:
  - firefox 140.6.0
  - 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-2025-14331'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2000218'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-92/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-93/'
    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
epss: 0.00187
epssPercentile: 0.07456
ingestedAt: '2026-09-30T17:13:20.757Z'
---

## Overview

Same-origin policy bypass in the Request Handling component. This vulnerability was fixed in Firefox 146, Firefox ESR 115.31, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

## Affected

- `firefox < 115.31.0`
- `firefox < 146.0`
- `firefox >= 116.0, < 140.6.0`
- `thunderbird < 140.6.0`
- `thunderbird < 146.0`

## Remediation

Upgrade past the affected range:

- `firefox 140.6.0`
- `thunderbird 146.0`