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Fencer Vulns
high 7.5

CVE-2023-37899 json

feathersjs socket handler allows abusing implicit toString

published 2023-07-19 3 y ago modified 2026-06-17 4 mo ago also GHSA-hhr9-rh25-hvf9 , EUVD-2023-2077

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. Feathers socket handler did not catch invalid string conversion errors like `const message = ${{ toString: '' }}` which would cause the NodeJS process to crash when sending an unexpected Socket.io message like `socket.emit('find', { toString: '' })`. A fix has been released in versions 5.0.8 and 4.5.18. Users are advised to upgrade. There is no known workaround for this vulnerability.

Patch / fix

  • npm @feathersjs/socketio 4.5.18, 5.0.8
  • npm @feathersjs/transport-commons 4.5.18, 5.0.8
  • feathersjs feathers 4.5.18, 5.0.8

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/feathersjs/feathers/security/advisories/GHSA-hhr9-rh25-hvf9 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm @feathersjs/socketio
<4.5.18
>=5.0.0, <5.0.8
4.5.18
5.0.8
npm @feathersjs/transport-commons
<4.5.18
>=5.0.0, <5.0.8
4.5.18
5.0.8

Affected products

  • feathersjs feathers

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.