CVE-2026-45736: ws is an open source WebSocket client and server for Node.js

Q: How do I fix CVE-2026-45736?

ws: upgrade to 8.20.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-45736 being exploited?

CVE-2026-45736 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-45736 affect?

CVE-2026-45736 affects ws. Severity is medium (CVSS 4.4). ws is an open source WebSocket client and server for Node.js. Prior to 8.20.1, the websocket.close() implementation is vulnerable to uninitialized memory disclosure when a TypedArray is passed as the reason argument. This vulnerability is f

Q: How urgent is CVE-2026-45736?

Priority 34/100. Public exploit reference

Routine

MEDIUM 4.4UPGRADE

CVE-2026-45736 is a medium-severity flaw (CVSS 4.4) affecting ws. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ws is an open source WebSocket client and server for Node.js. Prior to 8.20.1, the websocket.close() implementation is vulnerable to uninitialized memory disclosure when a TypedArray is passed as the reason argument. This vulnerability is fixed in 8.20.1.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.4 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	High
User interaction	None
EPSS exploit chance	0.7% (top 45%)
CISA exploited list	No
Weakness	CWE-908, CWE-824
Published	2026-05-15
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: ws project

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-15 15:16 UTCPublished CVE record published
2026-10-26 14:10 UTCUpdated Record last modified

ws project ws UPGRADE

Affected: >= 8.0.0 and < 8.20.1

Fixed in: 8.20.1

Safe to downgrade to: a release before 8.0.0

1. Check installed version

npm ls ws

2. UPGRADE to 8.20.1

npm install ws@">=8.20.1"

3. If no update is available yet, DOWNGRADE to a release before 8.0.0

npm view ws versions npm install ws@"<8.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45736?

ws: upgrade to 8.20.1. Exact commands for each OS are on this page.

Is CVE-2026-45736 being exploited?

CVE-2026-45736 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45736 affect?

CVE-2026-45736 affects ws. Severity is medium (CVSS 4.4). ws is an open source WebSocket client and server for Node.js. Prior to 8.20.1, the websocket.close() implementation is vulnerable to uninitialized memory disclosure when a TypedArray is passed as the reason argument. This vulnerability is f

How urgent is CVE-2026-45736?

Priority 34/100. Public exploit reference

Software pages

Node.js vulnerabilities

Related CVEs

CVE-2026-48779 HIGH 7.5 UPGRADE ws is an open source WebSocket client and server for Node.js

References

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