CVE-2026-2229

Aliases:GHSA-v9p9-hfj2-hcw8
Advisory lineage Upstream: 0 Downstream: 10
Analyzed
Published: 12 Mar 2026, 20:27
Last modified:15 Jul 2026, 01:19

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
0.87% LOW
1% probability +0.70%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

12 Mar 2026, 20:27
Published
Vulnerability first disclosed
15 Jul 2026, 01:19
Last Modified
Vulnerability information updated

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

CVSS Metrics

  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.87%• Percentile: 55%

Techniques & Countermeasures

  • CWE-248•Uncaught Exception

    An exception is thrown from a function, but it is not caught.

  • CWE-1284•Improper Validation of Specified Quantity in Input

    The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

Affected Systems

  • nodejs•undici

    < 6.24.0 | ≥ 7.0.0, < 7.24.0

  • Npm•undici

    < 6.24.0 | ≥ 7.0.0, < 7.24.0

  • undici•undici

    < 6.24.0; 7.0.0 < 7.24.0

References (25)