HTTP response splitting in Netty - CVE-2026-42578

Vulnerability identifier: #VU130212

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-42578

CWE-ID: CWE-113

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to inject arbitrary HTTP headers into CONNECT proxy requests.

The vulnerability exists due to improper neutralization of CRLF sequences in HTTP headers in io.netty.handler.proxy.HttpProxyHandler newInitialMessage() when handling user-influenced outbound headers. A remote attacker can supply crafted header values containing CRLF sequences to inject arbitrary HTTP headers into CONNECT proxy requests.

Exploitation requires an application to use HttpProxyHandler with user-influenced outboundHeaders without performing its own CRLF sanitization.

Netty
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Ubuntu
Development Tools Module
SUSE Package Hub 15
IBM SPSS Analytic Server
UCD - IBM UrbanCode Deploy
Red Hat OpenShift Dev Spaces
Red Hat Integration Camel Extensions for Quarkus
IBM Decision Optimization for Cloud Pak for Data
DevOps Deploy
Rational Performance Tester
DevOps Test Performance
netty-tcnative-debugsource
netty-tcnative
netty (Ubuntu package)
netty
netty-javadoc

Install security update from vendor's website.

Netty - addressed in versions 4.1.133, 4.2.13
UCD - IBM UrbanCode Deploy - addressed in versions 7.2.3.24, 7.3.2.19
DevOps Deploy - addressed in versions 8.0.1.14, 8.1.2.7, 8.2.2.0
DevOps Test Performance - update to 11.0.8
netty-tcnative-debugsource - update to 2.0.77-150200.3.39.1
netty-tcnative - update to 2.0.77-150200.3.39.1
netty (Ubuntu package) - addressed in versions 1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1, 1:4.0.34-1ubuntu0.1~esm4, 1:4.1.7-4ubuntu0.1+esm6, 1:4.1.45-1ubuntu0.1~esm6, 1:4.1.48-4+deb11u2ubuntu0.1+esm3, 1:4.1.48-9ubuntu0.1+esm3, 1:4.1.48-16ubuntu0.1~esm2
Red Hat OpenShift Dev Spaces - update to 3.28.2
Red Hat Integration Camel Extensions for Quarkus - update to 3.33.2
netty - update to 4.1.133-150200.4.46.1
netty-javadoc - update to 4.1.133-150200.4.46.1
IBM Decision Optimization for Cloud Pak for Data - update to 5.3.1 patch 6

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

• Multiple vulnerabilities in Netty
• IBM DevOps Test Performance update for Netty
• Multiple vulnerabilities in IBM SPSS Analytic Server
• Ubuntu update for netty
• SUSE update for netty, netty-tcnative
• Multiple vulnerabilities in Red Hat Integration Camel Extensions for Quarkus 3.33
• Multiple vulnerabilities in IBM Decision Optimization for Cloud Pak for Data
• Multiple vulnerabilities in Red Hat OpenShift Dev Spaces 3.28
• IBM DevOps Deploy / IBM UrbanCode Deploy (UCD) update for Netty