Uncaught Exception Affecting nodejs20-docs package, versions <1:20.20.1-1.amzn2023.0.3


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.19% (41st percentile)

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  • Snyk IDSNYK-AMZN2023-NODEJS20DOCS-15921246
  • published7 Apr 2026
  • disclosed12 Mar 2026

Introduced: 12 Mar 2026

NewCVE-2026-2229  (opens in a new tab)
CWE-248  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 nodejs20-docs to version 1:20.20.1-1.amzn2023.0.3 or higher.
This issue was patched in ALAS2023-2026-1524.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nodejs20-docs package and not the nodejs20-docs package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

CVSS Base Scores

version 3.1