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FirefoxWeb browser · Mozilla

CVE-2022-34478

MEDIUM · 6.5 CVSS v3.1 Published 2022-12-22
Fix available
A fix is available. Upgrade to 91.11 / 102.0 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
The <code>ms-msdt</code>, <code>search</code>, and <code>search-ms</code> protocols deliver content to Microsoft applications, bypassing the browser, when a user accepts a prompt. These applications have had known vulnerabilities, exploited in the wild (although we know of none exploited through Thunderbird), so in this release Thunderbird has blocked these protocols from prompting the user to open them.<br>*This bug only affects Thunderbird on Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 102, Firefox ESR < 91.11, Thunderbird < 102, and Thunderbird < 91.11.

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

Thunderbird on Windows allows ms-msdt, search, and search-ms protocols to deliver content to Microsoft applications, bypassing the browser's security model, when users accept a prompt. This enables potential exploitation of known vulnerabilities in those Microsoft applications. The fix blocks these protocols from prompting users.

MitigationUpgrade Thunderbird to version 102 or later (or 91.11 ESR) on Windows to receive the protocol blocking fix.

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:< 102.0
Firefox EsrWeb browser
Affected:< 91.11
ThunderbirdApplication
Affected:< 91.11

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. Confirm Windows platform
    Check if the system operating system is Windows. This vulnerability only affects Windows environments.
    Affected if System is not running Windows - the vulnerability does not apply to macOS or Linux.
  2. Identify installed Mozilla product
    Check if Mozilla Firefox, Firefox ESR, or Thunderbird is installed. Look in Program Files (or Program Files x86) for Firefox or Thunderbird directories, or check Start menu shortcuts.
    Affected if No Mozilla Firefox or Thunderbird installation found - the vulnerability does not apply.
  3. Check installed version
    Open the application, go to Help > About (or Menu > Help > About in Thunderbird), or check the version in the application binary properties. For command line, run: 'C:\Program Files\Mozilla Firefox\firefox.exe' -v or similar path.
    Affected if Version is 102.0 or higher (Firefox), 91.11 or higher (Firefox ESR/Thunderbird) - the vulnerability is patched. If version is below these thresholds on Windows, the system is affected.
  4. Verify protocol handling
    Attempt to access an ms-msdt, search, or search-ms URL (e.g., ms-msdt:anything) in the browser. On a vulnerable version, a prompt may appear asking to open a Microsoft application.
    Affected if The protocol prompt appears and user can accept it - the vulnerability is exploitable. If protocols are blocked or no prompt appears, the fix is active.

The system is affected if running Windows with Firefox < 102.0, Firefox ESR < 91.11, or Thunderbird < 91.11, and the ms-msdt, search, or search-ms protocol handlers can prompt the user.

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 91.11 / 102.0 or later
Fixed in 91.11102.0
Interim mitigation

Upgrade Thunderbird to version 102 or later (or 91.11 ESR) on Windows to receive the protocol blocking fix.

Recommended fix High confidence

Thunderbird 91.11+ (Windows), Firefox 102.0+, Firefox ESR 91.11+

  1. 1. Determine the currently installed Thunderbird version by navigating to Help > About Thunderbird
  2. 2. If running Thunderbird < 91.11 on Windows, download Thunderbird 91.11 or later from the official Mozilla Thunderbird website (www.thunderbird.net)
  3. 3. Close all Thunderbird instances completely
  4. 4. Run the downloaded installer and follow the prompts to complete the upgrade
  5. 5. Restart Thunderbird and verify the version in Help > About Thunderbird shows 91.11 or later
  6. 6. For Firefox users: If using Firefox < 102.0, upgrade to Firefox 102.0 or later. For Firefox ESR users: If using Firefox ESR < 91.11, upgrade to Firefox ESR 91.11 or later
Caveat This fix only applies to Thunderbird on Windows; other operating systems are unaffected. Ensure you back up your profile before upgrading.

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

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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-2022-34478 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