GHSA-v9p9-hfj2-hcw8

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Source
https://github.com/advisories/GHSA-v9p9-hfj2-hcw8
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-v9p9-hfj2-hcw8/GHSA-v9p9-hfj2-hcw8.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-v9p9-hfj2-hcw8
Aliases
Downstream
Related
Published
2026-03-13T20:41:41Z
Modified
2026-03-18T22:58:58.908047Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
Undici has Unhandled Exception in WebSocket Client Due to Invalid server_max_window_bits Validation
Details

Impact

The 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:

  1. The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15
  2. The createInflateRaw() call is not wrapped in a try-catch block
  3. The resulting exception propagates up through the call stack and crashes the Node.js process

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Database specific 
{
    "github_reviewed": true,
    "severity": "HIGH",
    "cwe_ids": [
        "CWE-248"
    ],
    "nvd_published_at": "2026-03-12T21:16:25Z",
    "github_reviewed_at": "2026-03-13T20:41:41Z"
}
References

Affected packages

npm / undici

Package

Name
undici
View open source insights on deps.dev
Purl
pkg:npm/undici

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.24.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-v9p9-hfj2-hcw8/GHSA-v9p9-hfj2-hcw8.json"

npm / undici

Package

Name
undici
View open source insights on deps.dev
Purl
pkg:npm/undici

Affected ranges

Type
SEMVER
Events
Introduced
7.0.0
Fixed
7.24.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-v9p9-hfj2-hcw8/GHSA-v9p9-hfj2-hcw8.json"