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CWE-180Weakness · CWE-180

CVE-2026-42462

HIGH · 7.0 CVSS v3.1 Published 2026-06-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
79/100
Remediation priority · High
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
Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3, an attacker can make use of JSON-LD features to restructure a JSON-LD document that would change how Fedify interprets it without changing its Linked Data Signature, allowing them to alter a third-party signed activity they have received. Versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3 fix the issue.

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

An attacker can exploit JSON-LD's flexible structure to restructure a JSON-LD document in a way that changes how Fedify interprets it, while the Linked Data Signature remains valid. This allows modification of signed ActivityPub activities received from third parties.

MitigationUpgrade Fedify to version 1.9.11, 1.10.10, 2.0.18, 2.1.14, 2.2.3 or later.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L

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 Fedify installation and version
    Locate the Fedify package in your project dependencies (package.json, Gemfile, go.mod, requirements.txt, or similar) and note the exact version number
    Affected if The installed version is earlier than 1.9.11, 1.10.10, 2.0.18, 2.1.14, or 2.2.3 (for example 1.9.10, 2.0.17, 2.1.13, etc.)
  2. Confirm Fedify is processing incoming ActivityPub content
    Review your Fedify server configuration or code to determine if the instance receives or processes signed activities or objects from other ActivityPub servers
    Affected if Your Fedify instance accepts or processes incoming JSON-LD signed activities from remote servers (this is the default behavior for most Fedify deployments)
  3. Check if remote signer validation is enabled
    Examine your Fedify configuration for settings related to signature verification, such as `verifySignatures`, `requireSignedRequests`, or similar options that control inbound signature validation
    Affected if Remote signature verification is enabled (the vulnerability allows bypass of this protection, so this is the vulnerable configuration)

You are affected if your Fedify version is below the fixed releases AND your instance processes signed ActivityPub content from other servers, which is the standard operation mode.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Fedify to version 1.9.11, 1.10.10, 2.0.18, 2.1.14, 2.2.3 or later.

Recommended fix High confidence

Upgrade to version 1.9.11, 1.10.10, 2.0.18, 2.1.14, or 2.2.3 depending on your current major.minor release line

  1. 1. Identify the current version of Fedify in your project by checking package.json or running npm list fedify
  2. 2. Determine which release line your current version belongs to (1.x, 2.x, etc.)
  3. 3. Upgrade to the appropriate fixed version for your release line: 1.9.11 for 1.x, 1.10.10 for 1.10.x, 2.0.18 for 2.0.x, 2.1.14 for 2.1.x, or 2.2.3 for 2.2.x
  4. 4. Run npm update fedify@<version> or yarn upgrade fedify@<version> to install the fixed version
  5. 5. Run your test suite to verify the upgrade does not break existing functionality
  6. 6. Redeploy your application with the updated dependency

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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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-2026-42462 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data