CVE-2023-32695Public exploitNetwork attack vector

Unauthenticated server crash via invalid event names

Published May 27, 2023 · Updated Jan 13, 2025

Improper input validation in Socket.IO socket.io-parser 3.4.0 through 3.4.2 and 4.0.4 through 4.2.2 allows remote attackers to crash the server. Decoder.isPayloadValid accepts any nonempty event array without requiring its first element to be a string or number, so an object can reach event-name handling. An unauthenticated Socket.IO client can supply an object with an invalid string conversion, causing EventEmitter coercion to throw an uncaught TypeError and terminate the Node.js process.

CVSS severity6.9
Medium
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Socket.IO socket.io-parser 3.4.0 through 3.4.2 and 4.0.4 through 4.2.2 allows remote attackers to crash the server. Decoder.isPayloadValid accepts any nonempty event array without requiring its first element to be a string or number, so an object can reach event-name handling. An unauthenticated Socket.IO client can supply an object with an invalid string conversion, causing EventEmitter coercion to throw an uncaught TypeError and terminate the Node.js process.

The record

CVE
CVE-2023-32695
Published
May 27, 2023
Updated
Jan 13, 2025
Vendor
Socket.IO
Product
socket.io-parser
Classifications
CWE-754, CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.4.0, < 3.4.3
  2. Affected versionversion=>= 4.0.0, < 4.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Socket.IO · socket.io-parserversion=>= 3.4.0, < 3.4.3; version=>= 4.0.0, < 4.2.3

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
CWE-20Improper Input Validation
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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