CVE-2026-1528

HIGH7.5EPSS 0.12%

Undici: Malicious WebSocket 64-bit length overflows parser and crashes the client

Published: 3/13/2026Modified: 3/18/2026

Also known as:GHSA-f269-vfmq-vjvjCGA-w442-vj6r-7j29

Description

### Impact A server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process. ### Patches Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later. ### Workarounds There are no workarounds.

Affected packages (2)

Debian/node-undicifrom 0
npm/undici>= 6.0.0, < 6.24.0

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	HIGH7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (6)

ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-1528
ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-1528
PATCHhttps://github.com/nodejs/undici
WEBhttps://cna.openjsf.org/security-advisories.html
WEBhttps://github.com/nodejs/undici/security/advisories/GHSA-f269-vfmq-vjvj
WEBhttps://hackerone.com/reports/3537648