CVE-2026-42578

Publication date 13 May 2026

Last updated 8 June 2026

Ubuntu priority

Cvss 3 Severity Score

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
netty	26.04 LTS resolute	Fixed 1:4.1.48-16ubuntu0.1~esm2
	25.10 questing	Vulnerable
	24.04 LTS noble	Fixed 1:4.1.48-9ubuntu0.1+esm3
	22.04 LTS jammy	Fixed 1:4.1.48-4+deb11u2ubuntu0.1+esm3
	20.04 LTS focal	Fixed 1:4.1.45-1ubuntu0.1~esm6
	18.04 LTS bionic	Fixed 1:4.1.7-4ubuntu0.1+esm6
	14.04 LTS trusty	Not affected

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
netty	Upstream: 137e3fa Upstream: 8485588

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References

Related Ubuntu Security Notices (USN)

USN-8401-1
Netty vulnerabilities
8 June 2026