CVE-2026-42578

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.

References

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42578.json

https://github.com/netty/netty/security/advisories/GHSA-45q3-82m4-75jr

https://bugzilla.redhat.com/show_bug.cgi?id=2477226

https://access.redhat.com/security/cve/CVE-2026-42578

https://access.redhat.com/errata/RHSA-2026:37390

https://access.redhat.com/errata/RHSA-2026:36820

https://access.redhat.com/errata/RHSA-2026:28010

https://access.redhat.com/errata/RHSA-2026:25123

https://access.redhat.com/errata/RHSA-2026:24502

https://access.redhat.com/errata/RHSA-2026:23808

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4

EPSS