dbcve.org
FirefoxWeb browser · Mozilla

CVE-2022-31742

MEDIUM · 6.5 CVSS v3.1 Published 2022-12-22
Fix available
A fix is available. Upgrade to 91.10 / 101 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
An attacker could have exploited a timing attack by sending a large number of allowCredential entries and detecting the difference between invalid key handles and cross-origin key handles. This could have led to cross-origin account linking in violation of WebAuthn goals. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.

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

A timing side-channel in Firefox and Thunderbird's WebAuthn implementation allows attackers to distinguish between invalid key handles and cross-origin key handles by measuring response times when sending large numbers of allowCredential entries. This enables cross-origin account linking that violates WebAuthn's isolation guarantees.

MitigationUpdate affected products to patched versions: Thunderbird >= 91.10, Firefox >= 101, or Firefox ESR >= 91.10.

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:< 101
Firefox EsrWeb browser
Affected:< 91.10
ThunderbirdApplication
Affected:< 91.10

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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
    Open Firefox, go to Menu > Help > About Firefox, or navigate to about:support. Locate the version number in the page that opens.
    Affected if The version shown is less than 101 (for example, 100.0, 98.0, etc.)
  2. Check Firefox ESR version
    Open Firefox ESR, go to Menu > Help > About Firefox ESR, or navigate to about:support. Locate the version number in the page that opens.
    Affected if The version shown is less than 91.10 (for example, 91.9, 91.0, etc.)
  3. Check Thunderbird version
    Open Thunderbird, go to Menu > Help > About Thunderbird. Locate the version number in the window that opens.
    Affected if The version shown is less than 91.10 (for example, 91.9, 78.x, etc.)

You are affected if any installed Firefox version is below 101, or any Firefox ESR or Thunderbird version is below 91.10, and the browser or mail client is used with WebAuthn-based authentication.

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 91.10 / 101 or later
Fixed in 91.10101
Interim mitigation

Update affected products to patched versions: Thunderbird >= 91.10, Firefox >= 101, or Firefox ESR >= 91.10.

Recommended fix High confidence

Firefox 101 or later; Firefox ESR 91.10 or later; Thunderbird 91.10 or later

  1. Determine your current Firefox, Firefox ESR, or Thunderbird version by navigating to the application menu and selecting 'Help' > 'About [Application]'
  2. If your version is below 101 (Firefox) or below 91.10 (Firefox ESR or Thunderbird), initiate an update
  3. For Firefox/Firefox ESR: Go to Menu > Help > About Firefox/About Firefox ESR and click 'Check for Updates' to download and install the latest version
  4. For Thunderbird: Go to Menu > Help > About Thunderbird and click 'Check for Updates' to download and install the latest version
  5. Alternatively, download the latest version directly from the official Mozilla website (www.mozilla.org) for your operating system
  6. Restart the application after the update completes
  7. Verify the update was successful by checking the version number again in Help > About
Caveat Minimal risk - standard Mozilla releases typically do not introduce breaking changes for end users

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
3.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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-2022-31742 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