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Fencer Vulns
critical 10.0

CVE-2022-2421 json

Socket.io - Improper type validation in attachment parsing

published 2022-10-25 4 y ago modified 2026-06-17 4 mo ago also GHSA-qm95-pgcg-qqfq , EUVD-2022-7153

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

Due to improper type validation in attachment parsing the Socket.io js library, it is possible to overwrite the _placeholder object which allows an attacker to place references to functions at arbitrary places in the resulting query object.

Patch / fix

  • npm socket.io-parser 3.3.3, 3.4.2, 4.0.5, 4.2.1
  • Socket.io Socket.io-Parser 4.2.1

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
23 mo ago

Exploit prediction

1.43% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm socket.io-parser
>=4.0.0, <4.0.5
>=4.1.0, <4.2.1
<3.3.3
>=3.4.0, <3.4.2
4.0.5
4.2.1
3.3.3
3.4.2

Affected products

  • Socket.io Socket.io-Parser

Classification

Weakness
  • CWE-89 Improper Neutralization of Special Elements used in an SQL Command
  • CWE-1287 Improper Validation of Specified Type of Input
  • CWE-20 Improper Input Validation

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.