---
id: CVE-2025-11720
title: >-
  The Firefox and Firefox Focus UI for the Android custom tab feature only
  showed the "site" that was loaded, not the full hostname
summary: >-
  The Firefox and Firefox Focus UI for the Android custom tab feature only
  showed the "site" that was loaded, not the full hostname. User supplied
  content hosted on a subdomain of a site could have been used to fool a user
  into thinking it…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N'
cwe:
  - CWE-451
vendor: mozilla
product: firefox
affected:
  - firefox < 144.0
patched:
  - firefox 144.0
published: '2025-10-14'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T17:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-11720'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1979534'
    label: security@mozilla.org
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1984370'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-81/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.00268
epssPercentile: 0.17067
ingestedAt: '2026-09-30T17:13:20.715Z'
---

## Overview

The Firefox and Firefox Focus UI for the Android custom tab feature only showed the "site" that was loaded, not the full hostname. User supplied content hosted on a subdomain of a site could have been used to fool a user into thinking it was content from a different subdomain of that site. This vulnerability was fixed in Firefox 144.

## Affected

- `firefox < 144.0`

## Remediation

Upgrade past the affected range:

- `firefox 144.0`