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FirefoxWeb browser · Mozilla

CVE-2023-29543

HIGH · 8.8 CVSS v3.1 Published 2023-06-02
Fix available
A fix is available. Upgrade to 112.0 or later.
See remediation →
95/100
Remediation priority · Urgent
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
An attacker could have caused memory corruption and a potentially exploitable use-after-free of a pointer in a global object's debugger vector. This vulnerability affects Firefox for Android < 112, Firefox < 112, and Focus for Android < 112.

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 · moderate confidence

A use-after-free vulnerability exists in Firefox's debugger subsystem where an attacker can cause memory corruption by accessing a freed pointer in a global object's debugger vector. This memory corruption can potentially be exploited for arbitrary code execution.

MitigationApply vendor-supplied patches by updating Firefox, Firefox for Android, and Focus for Android to version 112 or later.

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:< 112.0
FocusApplication
Affected:< 112.0

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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. Check installed Firefox version
    Run 'firefox --version' on Linux/macOS, check Help > About Firefox on Windows, or read the version from the application binary metadata
    Affected if Version is below 112.0 (for example 111.x, 110.x, etc.)
  2. Check installed Mozilla Focus version
    On Android, go to Settings > Apps > Mozilla Focus and view the version information under App info
    Affected if Version is below 112.0 (for example 111.x, 110.x, etc.)
  3. Verify Firefox update channel
    In Firefox, navigate to 'about:support' and look at the 'Update Channel' value in the Application Basics section. Also check 'Version' to confirm the exact installed version
    Affected if Update channel shows a version lower than 112.0, indicating an unpatched installation
  4. Confirm debugger accessibility
    In Firefox, open Developer Tools (F12 or Ctrl+Shift+I), then open the Debugger panel. Alternatively, navigate to 'about:debugging' to see available debug targets
    Affected if The debugger interface is accessible and functional, meaning the vulnerable debugger code path could be reached

You are affected if you have Firefox or Focus installed with a version lower than 112.0 and the browser's debugger functionality is accessible (which it is by default for local use).

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 112.0 or later
Fixed in 112.0
Interim mitigation

Apply vendor-supplied patches by updating Firefox, Firefox for Android, and Focus for Android to version 112 or later.

Recommended fix High confidence

Firefox 112.0 / Focus 112.0

  1. 1. Check the currently installed Firefox version by navigating to Menu > Help > About Firefox (or typing 'about:support' in the address bar)
  2. 2. Check the currently installed Focus version in the Android device settings under Apps > Focus > Version
  3. 3. For Firefox Desktop: Open the application, go to Menu > Help > About Firefox, and the update will automatically download and install version 112.0 or later
  4. 4. For Firefox Android: Open the Google Play Store, search for Firefox, and tap Update to install version 112.0 or later
  5. 5. For Focus for Android: Open the Google Play Store, search for 'Firefox Focus', and tap Update to install version 112.0 or later
  6. 6. After updating, restart the browser application to ensure all components are loaded with the patched version
  7. 7. Verify the update was successful by checking the version number in About (should show 112.0 or higher)
Caveat Standard minor version upgrade with no expected breaking changes; this is a routine security update

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.

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-2023-29543 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