---
id: CVE-2025-23109
title: >-
  Long hostnames in URLs could be leveraged to obscure the actual host of the
  website or spoof the website address
summary: >-
  Long hostnames in URLs could be leveraged to obscure the actual host of the
  website or spoof the website address. This vulnerability was fixed in Firefox
  for iOS 134.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N'
cwe:
  - CWE-346
vendor: mozilla
product: firefox
affected:
  - firefox < 134.0
patched:
  - firefox 134.0
published: '2025-01-11'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T19:10:01.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-23109'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1419275'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-06/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.00181
epssPercentile: 0.06934
ingestedAt: '2026-09-30T19:21:07.222Z'
---

## Overview

Long hostnames in URLs could be leveraged to obscure the actual host of the website or spoof the website address. This vulnerability was fixed in Firefox for iOS 134.

## Affected

- `firefox < 134.0`

## Remediation

Upgrade past the affected range:

- `firefox 134.0`