---
title: "CVE-2026-2229\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-2229?format=md
keywords: index, follow
---

# CVE-2026-2229

Publication date 12 March 2026

Last updated 18 March 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2026-2229?format=md#impact-score)

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## 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

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| node-undici | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-2229)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-2229)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-2229)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-2229)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-2229>