---
id: CVE-2025-8043
title: >-
  Focus incorrectly truncated URLs towards the beginning instead of around the
  origin
summary: >-
  Focus incorrectly truncated URLs towards the beginning instead of around the
  origin. This vulnerability was fixed in Firefox 141.
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-451
vendor: mozilla
product: firefox
affected:
  - firefox < 141.0
  - thunderbird < 141.0
patched:
  - firefox 141.0
  - thunderbird 141.0
published: '2025-07-22'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-8043'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1970209'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-56/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.00381
epssPercentile: 0.2957
ingestedAt: '2026-09-30T18:17:24.452Z'
---

## Overview

Focus incorrectly truncated URLs towards the beginning instead of around the origin. This vulnerability was fixed in Firefox 141.

## Affected

- `firefox < 141.0`
- `thunderbird < 141.0`

## Remediation

Upgrade past the affected range:

- `firefox 141.0`
- `thunderbird 141.0`