---
title: CVE-2026-59920
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-2026-59920
---

# CVE-2026-59920

Publication date 29 July 2026

Last updated 7 August 2026

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**6.5 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2026-59920#impact-score)

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## Description

Netty is an asynchronous, event-driven network application framework. In
versions prior to 4.1.136.Final and 4.2.16.Final, Netty's STOMP encoder
( StompSubframeEncoder ) does not escape or validate header values in
 CONNECT  and  CONNECTED  frames, so raw newline ( \n ) characters in a
header value are written directly to the wire, allowing an attacker who
controls a header value to inject additional STOMP headers. This happens
because the encoder intentionally skips escaping for CONNECT/CONNECTED
frames per the STOMP 1.2 specification but never rejects the raw newlines,
and since a broker parses each line as a separate header, an attacker
controlling a value such as a user-supplied login or passcode can overwrite
connection parameters or add authentication/role headers to bypass
authentication or escalate privileges (the actual impact is
broker-dependent). The issue is fixed in versions 4.1.136.Final and
4.2.16.Final.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| netty | 26.04 LTS resolute | Needs evaluation |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Needs evaluation |

---

* [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**

6.5 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.5 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-59920)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-59920)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-59920)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-59920)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-59920>
* <https://github.com/netty/netty/security/advisories/GHSA-3g8r-4pfx-jmfh>