CVE-2026-2229

7.5 HIGH
Published: March 12, 2026 Modified: March 20, 2026
View on NVD

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

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://cna.openjsf.org/security-advisories.html
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Vendor Advisory
https://datatracker.ietf.org/doc/html/rfc7692
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Technical Description
https://github.com/nodejs/undici/security/advisories/GHSA-v9p9-hfj2-hcw8
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Vendor Advisory
https://hackerone.com/reports/3487486
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Permissions Required
https://nodejs.org/api/zlib.html#class-zlibinflateraw
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Technical Description

5 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.1%
29th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

nodejs