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FirefoxWeb browser · Mozilla

CVE-2023-34415

MEDIUM · 6.1 CVSS v3.1 Published 2023-06-19
Fix available
A fix is available. Upgrade to 114.0 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable 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
When choosing a site-isolated process for a document loaded from a data: URL that was the result of a redirect, Firefox would load that document in the same process as the site that issued the redirect. This bypassed the site-isolation protections against Spectre-like attacks on sites that host an "open redirect". Firefox no longer follows HTTP redirects to data: URLs. This vulnerability affects Firefox < 114.

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

Firefox's site-isolation mechanism was bypassed when processing redirects to data: URLs. When a site with an open redirect issued an HTTP redirect to a data: URL, Firefox incorrectly loaded that document in the same process as the redirecting site rather than isolating it, allowing Spectre-like attacks to potentially access sensitive data from the redirecting origin.

MitigationUpgrade to Firefox version 114 or later. Organizations can also configure enterprise policies to block navigation to data: URLs as an interim measure.

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:< 114.0

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
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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. Check Firefox version via command line
    Open a terminal and run 'firefox --version' or 'firefox -v' to display the installed Firefox version number
    Affected if The displayed version is lower than 114.0 (for example, 113.0.1 or 113.0)
  2. Check Firefox version via About dialog
    Open Firefox, click the menu button (three horizontal lines), select Help, then select About Firefox. The version number is displayed on this page
    Affected if The version shown is below 114.0 (for example, 112.0.2 or 113.x)
  3. Check Firefox version in enterprise deployment
    For managed Windows systems, check the version in Programs and Features or use 'wmic product get name,version' to list installed Mozilla Firefox version
    Affected if The recorded version is earlier than 114.0 (for example, 111.0 or 112.0.1)
  4. Check Firefox version on macOS
    Open Finder, go to Applications folder, right-click Firefox, select Get Info, or run '/Applications/Firefox.app/Contents/MacOS/firefox --version' in Terminal
    Affected if The version shown is less than 114.0 (for example, 113.0.3 or any 112.x release)

You are affected if the installed Firefox version is below 114.0, as versions prior to 114.0 contain the site-isolation bypass vulnerability when processing redirects to data: 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 114.0 or later
Fixed in 114.0
Interim mitigation

Upgrade to Firefox version 114 or later. Organizations can also configure enterprise policies to block navigation to data: URLs as an interim measure.

Recommended fix High confidence

Firefox 114.0

  1. Open Firefox and click the menu button (three horizontal lines) in the top right corner
  2. Select 'Help' from the dropdown menu
  3. Click 'About Firefox' from the Help submenu
  4. The About Firefox window will check for updates automatically. If Firefox 114.0 is available, it will begin downloading
  5. Once the download completes, click 'Restart to update Firefox' to install version 114.0
  6. After Firefox restarts, verify the version by going to Menu > Help > About Firefox - it should show version 114.0 or later
Caveat Minor version upgrades typically have no breaking changes; however, some older extensions may be incompatible

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

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing2.0 h
  • Review / QA1.0 h
13.0 hours of engineering $2,320
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,712.

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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-2023-34415 in production — separate from our analysis above.

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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