USN-8401-1: Netty vulnerabilities

Publication date

8 June 2026

Overview

Several security issues were fixed in Netty.


Packages

  • netty - event-driven asynchronous network application framework

Details

It was discovered that Netty's HTTP proxy handler did not properly
validate headers when constructing CONNECT requests. An
attacker could possibly use this issue to inject arbitrary HTTP
headers into CONNECT requests. This issue only affected Ubuntu
18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,
and Ubuntu 26.04 LTS. (CVE-2026-42578)

It was discovered that Netty's DNS codec did not properly enforce
domain name constraints. An attacker could possibly use this issue to
bypass domain name validation, or cause Netty to consume resources,
leading to a denial of service. This issue only affected Ubuntu 20.04
LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-42579)

It was discovered that Netty did not correctly handle HTTP/1.0
requests containing both a Transfer-Encoding and Content-Length
header. A remote...

It was discovered that Netty's HTTP proxy handler did not properly
validate headers when constructing CONNECT requests. An
attacker could possibly use this issue to inject arbitrary HTTP
headers into CONNECT requests. This issue only affected Ubuntu
18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,
and Ubuntu 26.04 LTS. (CVE-2026-42578)

It was discovered that Netty's DNS codec did not properly enforce
domain name constraints. An attacker could possibly use this issue to
bypass domain name validation, or cause Netty to consume resources,
leading to a denial of service. This issue only affected Ubuntu 20.04
LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-42579)

It was discovered that Netty did not correctly handle HTTP/1.0
requests containing both a Transfer-Encoding and Content-Length
header. A remote attacker could possibly use this issue to perform
HTTP request smuggling attacks. (CVE-2026-42581)

Violeta Georgieva discovered that Netty incorrectly paired responses with
requests when handling informational HTTP responses. A remote attacker
could possibly use this issue to perform HTTP request smuggling attacks.
(CVE-2026-42584)

Violeta Georgieva discovered that Netty incorrectly parsed malformed
Transfer-Encoding headers. A remote attacker could possibly use this
issue to perform HTTP request smuggling attacks. (CVE-2026-42585)

It was discovered that Netty's Redis encoder did not validate CRLF
characters. An attacker could possibly use this issue to inject arbitrary
Redis commands. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04
LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-42586)


Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.04 LTS resolute libnetty-java –  1:4.1.48-16ubuntu0.1~esm2  
24.04 LTS noble libnetty-java –  1:4.1.48-9ubuntu0.1+esm3  
22.04 LTS jammy libnetty-java –  1:4.1.48-4+deb11u2ubuntu0.1+esm3  
20.04 LTS focal libnetty-java –  1:4.1.45-1ubuntu0.1~esm6  
18.04 LTS bionic libnetty-java –  1:4.1.7-4ubuntu0.1+esm6  
16.04 LTS xenial libnetty-java –  1:4.0.34-1ubuntu0.1~esm4
14.04 LTS trusty libnetty-java –  1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1  

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