CVE-2022-39386Public exploitNetwork attack vector

Remote service crash via unhandled WebSocket stream error

Published Nov 8, 2022 · Updated Apr 23, 2025

Uncaught exception in Fastify @fastify/websocket 4.3.0 and earlier, 5.0.0, and 6.0.0 through 7.1.0 allows remote attackers to crash Node.js. The plugin creates a WebSocket stream without an error listener, so a frame with reserved bits set emits an unhandled error that terminates Node.js. Exploitation requires network access to a WebSocket route; the demonstrated consequence is a service crash, not data access or modification.

CVSS severity7.5
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncaught exception in Fastify @fastify/websocket 4.3.0 and earlier, 5.0.0, and 6.0.0 through 7.1.0 allows remote attackers to crash Node.js. The plugin creates a WebSocket stream without an error listener, so a frame with reserved bits set emits an unhandled error that terminates Node.js. Exploitation requires network access to a WebSocket route; the demonstrated consequence is a service crash, not data access or modification.

The record

CVE
CVE-2022-39386
Published
Nov 8, 2022
Updated
Apr 23, 2025
Vendor
Fastify
Product
@fastify/websocket
Classifications
CWE-248, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 8, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 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=<= 4.3.0
  2. Affected versionversion=>= 5.0.0, < 5.0.1
  3. Affected versionversion=>= 6.0.0, < 7.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fastify · @fastify/websocketversion=<= 4.3.0; version=>= 5.0.0, < 5.0.1; version=>= 6.0.0, < 7.1.1

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-248Uncaught Exception
T1499.004Application or System Exploitation

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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