Feathers socket handler allows abusing implicit toString

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2023-37899: 1.19% estimated exploitation activity in the next 30 days; percentile 67.94 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Feathers socket handler did not catch invalid string conversion errors like: Causing the NodeJS process to crash when sending an unexpected Socket.io message like Patches A fix has been released in - v5.0.8 via #3241 - v4.5.18 via #3242 Workarounds Since it is in the core Socket handling code upgrading to the latest version is necessary. References - v5.0.8 Changelog - v4.5.18 Changelog

Published by the source

20 Jul 2023, 14:54 UTC

Last modified by the source

8 Nov 2023, 04:13 UTC

Source last checked

26 Oct 2026, 12:27 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hhr9-rh25-hvf9

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hhr9-rh25-hvf9

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# Patch Next advisory brief: CVE-2023-37899

Advisory: Feathers socket handler allows abusing implicit toString
IDs: CVE-2023-37899, GHSA-hhr9-rh25-hvf9
Record: https://patchnext.com/advisories/cve-2023-37899 (revision 2, source checked 26 Oct 2026, 12:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @feathersjs/socketio 5.0.8, 4.5.18; @feathersjs/transport-commons 5.0.8, 4.5.18. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @feathersjs/socketio: affected <= 4.5.17; >= 5.0.0, <= 5.0.7; fixed in 5.0.8, 4.5.18
- npm @feathersjs/transport-commons: affected <= 4.5.17; >= 5.0.0, <= 5.0.7; fixed in 5.0.8, 4.5.18

## Suggested inspection (read-only)
- `npm ls @feathersjs/socketio --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @feathersjs/transport-commons --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @feathersjs/socketio, @feathersjs/transport-commons.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-hhr9-rh25-hvf9 (OSV record GHSA-hhr9-rh25-hvf9 lists affected ranges: npm @feathersjs/socketio >=0 =5.0.0 =0 =5.0.0 <5.0.8 (fixed))
- Verified: https://github.com/advisories/GHSA-hhr9-rh25-hvf9 (GitHub-reviewed advisory GHSA-hhr9-rh25-hvf9 lists affected ranges: npm @feathersjs/socketio >=0 =5.0.0 =0 =5.0.0 <=5.0.7)

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