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FeathersApplication · Feathersjs

CVE-2026-29793

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 5.0.42 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
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. From 5.0.0 to before 5.0.42, Socket.IO clients can send arbitrary JavaScript objects as the id argument to any service method (get, patch, update, remove). The transport layer performs no type checking on this argument. When the service uses the MongoDB adapter, these objects pass through getObjectId() and land directly in the MongoDB query as operators. Sending {$ne: null} as the id matches every document in the collection. This vulnerability is fixed in 5.0.42.

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

The FeathersJS transport layer (Socket.IO) fails to validate the type of the `id` parameter passed to service methods. When the MongoDB adapter is used, these arbitrary objects pass through getObjectId() and are injected directly into MongoDB queries as operators. An attacker can send {$ne: null} as the id to match all documents in a collection, enabling unauthorized data access or modification.

MitigationUpgrade FeathersJS to version 5.0.42 or later. Until upgrade is possible, implement input validation on all service method parameters to reject non-string/numeric id values before they reach the MongoDB adapter.

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
FeathersApplication
Affected:>= 5.0.0, < 5.0.42

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. Check FeathersJS version
    Run 'npm list @feathersjs/feathers' or check package.json dependencies to determine the installed version of @feathersjs/feathers
    Affected if Version is >= 5.0.0 and < 5.0.42
  2. Confirm Socket.IO transport is in use
    Inspect your server configuration files for Socket.IO setup (commonly in src/socket.js, src/index.js, or app.js). Look for feathers.socketio() or socket.io initialization
    Affected if Socket.IO transport is enabled and accepts client connections
  3. Verify MongoDB adapter is used
    Check package.json for @feathersjs/mongodb or feathers-mongodb dependency, and verify MongoDB is configured as the database adapter in your service configurations
    Affected if MongoDB adapter is configured for any service
  4. Inspect id validation on service methods
    Examine transport layer code (Socket.IO handlers) for any input validation or type casting applied to the 'id' parameter before passing to service methods. Look for explicit checks rejecting non-string/non-ObjectId id values
    Affected if No validation exists and raw id values are passed directly to MongoDB queries

You are affected if FeathersJS version is 5.0.0-5.0.42, Socket.IO transport is enabled, MongoDB adapter is used, and no input validation filters malicious id objects like {$ne: null} before queries.

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 5.0.42 or later
Fixed in 5.0.42
Interim mitigation

Upgrade FeathersJS to version 5.0.42 or later. Until upgrade is possible, implement input validation on all service method parameters to reject non-string/numeric id values before they reach the MongoDB adapter.

Recommended fix High confidence

5.0.42

  1. Check the current Feathers version in package.json to confirm the application is using an affected version (>=5.0.0, <5.0.42)
  2. Run 'npm install [email protected]' or update package.json to specify "feathers": "^5.0.42" and run npm install
  3. Verify the upgrade was successful by checking the installed version with npm list feathers
  4. Test the application, specifically service methods (get, patch, update, remove) that use the MongoDB adapter, to ensure functionality is intact
  5. Ensure that Socket.IO clients can no longer send arbitrary objects as the id parameter - the type checking should now reject non-string/non-objectid values

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

Fix this in Feathers Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
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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-2026-29793 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
  • 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