dbcve.org
FirefoxWeb browser · Mozilla

CVE-2024-26283

HIGH · 7.8 CVSS v3.1 Published 2024-02-22
Fix available
A fix is available. Upgrade to 123.0 or later.
See remediation →
81/100
Remediation priority · High
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An attacker could have executed unauthorized scripts on top origin sites using a JavaScript URI when opening an external URL with a custom Firefox scheme. This vulnerability affects Firefox for iOS < 123.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Cross-site scripting vulnerability in Firefox for iOS allows execution of unauthorized JavaScript via malicious JavaScript URIs when opening external URLs through custom Firefox scheme handlers, enabling script execution in the context of top-origin sites.

MitigationUpgrade Firefox for iOS to version 123 or later to patch the vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FirefoxWeb browser
Affected:< 123.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Firefox for iOS is installed
    Check the iOS device for the Firefox app in the app library or home screen. Navigate to Settings > Firefox to verify the app exists.
    Affected if Firefox for iOS is present on the device
  2. Identify the installed Firefox for iOS version
    Open the Firefox app, tap the menu (three lines) > Settings > About Firefox. The version number is displayed at the top of the screen.
    Affected if The displayed version number is less than 123.0 (for example, 122.x, 121.x, etc.)
  3. Verify if custom URL schemes are in use
    Check if any apps or web links are configured to open URLs through Firefox using custom schemes (such as firefox:// or fx://). This can be observed in iOS Settings > Firefox > Open Links in Firefox settings, or by attempting to open a link from another app.
    Affected if Firefox for iOS is set as the handler for external URLs and custom scheme URLs can be opened through it

A user is affected if Firefox for iOS version is below 123.0 and the app is configured to handle external URLs or custom scheme URLs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 123.0 or later
Fixed in 123.0
Interim mitigation

Upgrade Firefox for iOS to version 123 or later to patch the vulnerability.

Recommended fix Moderate confidence

Firefox for iOS 123.0

  1. Upgrade Firefox for iOS to version 123.0 or later by opening the App Store and updating the application

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
3.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-26283 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data