dbcve.org
FirefoxWeb browser · Mozilla

CVE-2023-28163

MEDIUM · 6.5 CVSS v3.1 Published 2023-06-02
Fix available
A fix is available. Upgrade to 102.9 / 111.0 or later.
See remediation →
72/100
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 downloading files through the Save As dialog on Windows with suggested filenames containing environment variable names, Windows would have resolved those in the context of the current user. <br>*This bug only affects Firefox on Windows. Other versions of Firefox are unaffected.*. This vulnerability affects Firefox < 111, Firefox ESR < 102.9, and Thunderbird < 102.9.

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 on Windows fails to sanitize environment variable names (like %USERPROFILE%, %TEMP%) in suggested filenames within the Save As dialog. Windows automatically resolves these variables to their actual paths, potentially causing files to be saved to unintended directories and enabling path-based attacks.

MitigationUpgrade to Firefox 111+, Firefox ESR 102.9+, or Thunderbird 102.9+ which contain the fix for environment variable resolution in download filenames.

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:< 111.0
Firefox EsrWeb browser
Affected:< 102.9
ThunderbirdApplication
Affected:< 102.9

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
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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. Identify your installed Mozilla product
    Open the application and go to Help > About (Firefox or Thunderbird) to see the exact version number, or check the program's file properties
    Affected if The product is Firefox below 111.0, Firefox ESR below 102.9, or Thunderbird below 102.9
  2. Confirm you are running Windows
    Check your operating system by running 'systeminfo' in command prompt or checking System Properties
    Affected if The operating system is Windows - this vulnerability only affects Windows environments
  3. Check for environment variable resolution in downloads
    Attempt a download and observe the default Save As path - if %USERPROFILE%, %TEMP%, or similar environment variables in the suggested filename are automatically resolved to actual paths (e.g., C:\Users\YourName\...) rather than appearing as literal text, the vulnerability is present
    Affected if Environment variables in suggested filenames are automatically resolved to their actual path values by Windows

You are affected if you run a vulnerable version of Firefox or Thunderbird on Windows and observe environment variables being resolved in the Save As dialog's suggested filename.

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 102.9 / 111.0 or later
Fixed in 102.9111.0
Interim mitigation

Upgrade to Firefox 111+, Firefox ESR 102.9+, or Thunderbird 102.9+ which contain the fix for environment variable resolution in download filenames.

Recommended fix High confidence

Firefox 111.0, Firefox ESR 102.9, or Thunderbird 102.9

  1. Check current Firefox or Thunderbird version via Help > About Firefox/Thunderbird
  2. Download Firefox 111.0 or later (or Firefox ESR 102.9 or later) from the official Mozilla website
  3. Download Thunderbird 102.9 or later if applicable
  4. Install the updated version, ensuring you close the application first
  5. Restart the browser after installation

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

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,440
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,904.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-28163 — 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-2023-28163 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