CVE-2026-2229

CVE Details

Release Date:	2026-03-12
Impact:	Important	What is this?

Description

ImpactThe undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination. The vulnerability exists because: * The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15 * The createInflateRaw() call is not wrapped in a try-catch block * The resulting exception propagates up through the call stack and crashes the Node.js process

See more information about CVE-2026-2229 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	7.5
Vector String:	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (nodejs22)	ELSA-2026-7080	2026-04-08
Oracle Linux version 8 (nodejs)	ELSA-2026-7123	2026-04-09
Oracle Linux version 8 (nodejs-nodemon)	ELSA-2026-7123	2026-04-09
Oracle Linux version 8 (nodejs-packaging)	ELSA-2026-7123	2026-04-09
Oracle Linux version 9 (nodejs)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-nodemon)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs-nodemon)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-packaging)	ELSA-2026-7302	2026-04-10
Oracle Linux version 9 (nodejs-packaging)	ELSA-2026-7350	2026-04-10