dbcve.org
FirefoxWeb browser · Mozilla

CVE-2023-29532

MEDIUM · 5.5 CVSS v3.1 Published 2023-06-19
Fix available
A fix is available. Upgrade to 102.10 / 112.0 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

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
A local attacker can trick the Mozilla Maintenance Service into applying an unsigned update file by pointing the service at an update file on a malicious SMB server. The update file can be replaced after the signature check, before the use, because the write-lock requested by the service does not work on a SMB server. *Note: This attack requires local system access and only affects Windows. Other operating systems are not affected.* This vulnerability affects Firefox < 112, Firefox ESR < 102.10, and Thunderbird < 102.10.

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

The Mozilla Maintenance Service on Windows has a time-of-check-to-time-of-use (TOCTOU) race condition. The service checks the signature of an update file but does not hold a valid file lock on SMB shares, allowing a local attacker to replace the signed file with a malicious unsigned update file after the signature validation but before use.

MitigationUpdate to Firefox 112+, Firefox ESR 102.10+, or Thunderbird 102.10+ on all Windows systems. Alternatively, restrict SMB access and limit local user privileges to minimize attack surface.

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
Firefox EsrWeb browser
Affected:< 102.10
ThunderbirdApplication
Affected:< 102.10

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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. Verify Windows operating system
    Check if the system is running Windows. This vulnerability only affects the Mozilla Maintenance Service on Windows platforms.
    Affected if The system is not running Windows - the vulnerability does not apply to other operating systems.
  2. Confirm Mozilla Maintenance Service presence
    Check if the Mozilla Maintenance Service is installed. On Windows, go to Services (services.msc) or check Program Files for Mozilla maintenance service components, or run: Get-Service | Where-Object {$_.Name -like '*Mozilla*'}
    Affected if The Mozilla Maintenance Service is not installed - the vulnerability only applies when this service exists.
  3. Identify installed Mozilla product and version
    Check installed version of Firefox or Thunderbird. For Firefox: Check Help > About Firefox or run firefox --version. For Thunderbird: Check Help > About Thunderbird or run thunderbird --version.
    Affected if No Mozilla product (Firefox or Thunderbird) is installed on the Windows system.
  4. Compare version against vulnerable ranges
    Compare your installed Firefox or Thunderbird version to the affected ranges: Firefox < 102.10 (or any version < 112.0), Firefox ESR < 102.10, Thunderbird < 102.10
    Affected if The installed version falls within the affected ranges (Firefox < 112.0, Firefox ESR < 102.10, Thunderbird < 102.10), indicating the system may be vulnerable.

A Windows system with Mozilla Maintenance Service present and an affected Firefox/Thunderbird version (< 112.0 for Firefox, < 102.10 for ESR/Thunderbird) is vulnerable to this TOCTOU race condition.

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 102.10 / 112.0 or later
Fixed in 102.10112.0
Interim mitigation

Update to Firefox 112+, Firefox ESR 102.10+, or Thunderbird 102.10+ on all Windows systems. Alternatively, restrict SMB access and limit local user privileges to minimize attack surface.

Recommended fix High confidence

Firefox 112.0, Firefox ESR 102.10, or Thunderbird 102.10

  1. Open Firefox or Thunderbird
  2. Click the menu button (three horizontal lines) and select 'Help'
  3. Select 'About Firefox' or 'About Thunderbird'
  4. The application will check for updates and download them automatically
  5. Click 'Update' or 'Restart to Update' when prompted
  6. Alternatively, download the latest version from https://www.mozilla.org/firefox/ or https://www.thunderbird.net/ and run the installer
Caveat Verify that any installed extensions are compatible with the new version; some older extensions may not function properly after upgrade

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

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-29532 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-29532 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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