GHSA-58QX-3VCG-4XPX

Vulnerability from github – Published: 2026-05-18 19:02 – Updated: 2026-05-18 19:02
VLAI
Summary
ws: Uninitialized memory disclosure
Details

Impact

The websocket.close() implementation is vulnerable to uninitialized memory disclosure when a TypedArray is passed as the reason argument.

Proof of concept

import { deepStrictEqual } from 'node:assert';
import { WebSocket, WebSocketServer } from 'ws';

const wss = new WebSocketServer(
  { port: 0, skipUTF8Validation: true },
  function () {
    const { port } = wss.address();
    const ws = new WebSocket(`ws://localhost:${port}`, {
      skipUTF8Validation: true
    });

    ws.on('close', function (code, reason) {
      deepStrictEqual(reason, Buffer.alloc(80));
    });
  }
);

wss.on('connection', function (ws) {
  ws.close(1000, new Float32Array(20));
});

Patches

The vulnerability was fixed in ws@8.20.1 (https://github.com/websockets/ws/commit/c0327ec15a54d701eb6ccefaa8bef328cfc03086).

Credits

Credit for the private and responsible disclosure of this issue goes to Nikita Skovoroda.

Remarks

Although the calculated CVSS severity is medium, the actual severity is believed to be low, as the flaw is only exploitable through misuse that is unlikely in practice.

Resources

  • https://github.com/advisories/GHSA-58qx-3vcg-4xpx
  • https://www.cve.org/CVERecord?id=CVE-2026-45736
Severity
4.4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "ws"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.20.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45736"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-18T19:02:40Z",
    "nvd_published_at": "2026-05-15T15:16:54Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nThe `websocket.close()` implementation is vulnerable to uninitialized memory disclosure when a `TypedArray` is passed as the reason argument.\n\n### Proof of concept\n\n```js\nimport { deepStrictEqual } from \u0027node:assert\u0027;\nimport { WebSocket, WebSocketServer } from \u0027ws\u0027;\n\nconst wss = new WebSocketServer(\n  { port: 0, skipUTF8Validation: true },\n  function () {\n    const { port } = wss.address();\n    const ws = new WebSocket(`ws://localhost:${port}`, {\n      skipUTF8Validation: true\n    });\n\n    ws.on(\u0027close\u0027, function (code, reason) {\n      deepStrictEqual(reason, Buffer.alloc(80));\n    });\n  }\n);\n\nwss.on(\u0027connection\u0027, function (ws) {\n  ws.close(1000, new Float32Array(20));\n});\n```\n\n### Patches\n\nThe vulnerability was fixed in ws@8.20.1 (https://github.com/websockets/ws/commit/c0327ec15a54d701eb6ccefaa8bef328cfc03086).\n\n### Credits\n\nCredit for the private and responsible disclosure of this issue goes to [Nikita Skovoroda](https://github.com/ChALkeR).\n\n### Remarks\n\nAlthough the calculated CVSS severity is medium, the actual severity is believed to be low, as the flaw is only exploitable through misuse that is unlikely in practice.\n\n### Resources\n\n- https://github.com/advisories/GHSA-58qx-3vcg-4xpx\n- https://www.cve.org/CVERecord?id=CVE-2026-45736",
  "id": "GHSA-58qx-3vcg-4xpx",
  "modified": "2026-05-18T19:02:40Z",
  "published": "2026-05-18T19:02:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/security/advisories/GHSA-58qx-3vcg-4xpx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45736"
    },
    {
      "type": "WEB",
      "url": "https://github.com/websockets/ws/commit/c0327ec15a54d701eb6ccefaa8bef328cfc03086"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/websockets/ws"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ws: Uninitialized memory disclosure"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.