---
id: CVE-2021-29993
title: >-
  Firefox for Android allowed navigations through the `intent://` protocol,
  which could be used to cause crashes and UI spoofs
summary: >-
  Firefox for Android allowed navigations through the `intent://` protocol,
  which could be used to cause crashes and UI spoofs. *This bug only affects
  Firefox for Android. Other operating systems are unaffected.*. This
  vulnerability affect…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H'
vendor: mozilla
product: firefox_mobile
affected:
  - firefox_mobile < 92.0
patched:
  - firefox_mobile 92.0
published: '2021-11-03'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-29993'
references:
  - url: >-
      https://bugzilla.mozilla.org/buglist.cgi?bug_id=1712242%2C1708767%2C1712240%2C1708544%2C1729259
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2021-38/'
    label: security@mozilla.org
  - url: >-
      https://bugzilla.mozilla.org/buglist.cgi?bug_id=1712242%2C1708767%2C1712240%2C1708544%2C1729259
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2021-38/'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00726
epssPercentile: 0.52159
ingestedAt: '2026-08-19T15:41:15.191Z'
---

## Overview

Firefox for Android allowed navigations through the `intent://` protocol, which could be used to cause crashes and UI spoofs. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92.

## Affected

- `firefox_mobile < 92.0`

## Remediation

Upgrade past the affected range:

- `firefox_mobile 92.0`