CVE-2026-2229

Published: March 13, 2026Last modified: June 16, 2026

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

Severity score breakdown

Parameter	Value
Base score	7.5
Attack Vector	NETWORK
Attack complexity	LOW
Privileges required	NONE
User interaction	NONE
Scope	UNCHANGED
Confidentiality	NONE
Integrity impact	NONE
Availability impact	HIGH
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Status

Product	Release	Package	Status
Alpaquita Linux	23 LTS	nodejs	Fixed (20.20.2-r0)
	25 LTS	nodejs	Fixed (22.22.2-r0)
	Stream	nodejs	Fixed (24.16.0-r0)
Hardened Containers	23 LTS	nodejs	Fixed (20.20.2-r0)
	25 LTS	nodejs	Fixed (22.22.2-r0)
	Stream	nodejs	Fixed (24.16.0-r0)

CVE-2026-2229

Description

Severity score breakdown

Status

References