MastodonApplication · Joinmastodon

CVE-2022-24307

CRITICAL · 9.8 CVSS v3.1 Published 2022-02-03
Fix available
A fix is available. Upgrade to 3.3.2 / 3.4.6 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
Mastodon before 3.3.2 and 3.4.x before 3.4.6 has incorrect access control because it does not compact incoming signed JSON-LD activities. (JSON-LD signing has been supported since version 1.6.0.)

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

Mastodon versions before 3.3.2 and 3.4.6 contain an incorrect access control vulnerability due to failure to compact incoming signed JSON-LD activities. This allows attackers to bypass authentication and authorization checks in the ActivityPub federation protocol by sending specially crafted JSON-LD that bypasses signature verification.

MitigationUpgrade Mastodon to version 3.3.2 or 3.4.6 or later to patch the vulnerability. This is a critical security update that should be prioritized given the CVSS 9.8 score.

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
MastodonApplication
Affected:< 3.3.2>= 3.4.0, < 3.4.6

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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. Determine installed Mastodon version
    Check the version file in the Mastodon installation directory, the Gemfile.lock, or the admin dashboard under Site Settings. Common locations include the VERSION file in the root directory or running 'git describe --tags' if installed from source.
    Affected if Version is below 3.3.2 or between 3.4.0 and 3.4.5 (inclusive)
  2. Verify ActivityPub federation is enabled
    Check Mastodon's site settings or configuration file (config/settings.yml) for the 'activitypub' or 'federation' enabled status. In the admin interface, confirm that federated timeline (FEP) is not disabled.
    Affected if ActivityPub federation is currently active (this is the default and typical configuration)
  3. Inspect inbound JSON-LD processing
    Review web server and application logs for any unusual or malformed JSON-LD activity submissions, particularly those involving the /inbox endpoints. Check if there are any existing signatures that appear to bypass standard verification.
    Affected if Unusual inbound ActivityPub requests are observed or if signature validation has been bypassed historically
  4. Check for unauthorized access indicators
    Review account moderation logs, audit logs, and remote follow requests for signs of unauthorized account access or actions performed by federated accounts that should have been rejected.
    Affected if Any unauthorized federated account actions are found that bypassed normal authentication

You are affected if running Mastodon version 3.3.0-3.3.1 or 3.4.0-3.4.5 with ActivityPub federation enabled, as the JSON-LD compaction flaw allows signature verification bypass on inbound federation requests.

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 3.3.2 / 3.4.6 or later
Fixed in 3.3.23.4.6
Interim mitigation

Upgrade Mastodon to version 3.3.2 or 3.4.6 or later to patch the vulnerability. This is a critical security update that should be prioritized given the CVSS 9.8 score.

Recommended fix High confidence

Mastodon 3.3.2 or 3.4.6 (or latest stable release in your minor branch)

  1. Ensure you have a backup of your Mastodon instance before upgrading
  2. Determine your current Mastodon version by checking your installation
  3. If running < 3.3.2, upgrade to version 3.3.2 or later
  4. If running >= 3.4.0 and < 3.4.6, upgrade to version 3.4.6 or later
  5. Follow standard Mastodon upgrade procedures for your deployment method (e.g., source, Docker, or package manager)
  6. After upgrading, verify the instance is functioning correctly and monitor for any issues
Caveat Check Mastodon release notes for your target version for any breaking changes or required migration steps

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

Fix this in Mastodon Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-24307 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2022-24307 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