Netty HttpProxyHandler Header Injection (4.2.13.Final/4.1.133.Final)
CVE-2026-42578 Published on May 13, 2026

Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation
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.

NVD

Vulnerability Analysis

CVE-2026-42578 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-42578. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
HIGH
Availability Impact:
NONE

Weakness Types

What is a HTTP Response Splitting Vulnerability?

The software receives data from an upstream component, but does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.

CVE-2026-42578 has been classified to as a HTTP Response Splitting vulnerability or weakness.

What is a CRLF Injection Vulnerability?

The software uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

CVE-2026-42578 has been classified to as a CRLF Injection vulnerability or weakness.


Products Associated with CVE-2026-42578

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-42578 are published in these products:

Netty
 
Canonical Ubuntu Linux
 
Red Hat Cryostat
 
Red Hat Openshift Devspaces
 
Red Hat Quarkus
 
Red Hat Serverless
 
Red Hat Amq Broker
 
Red Hat Amq Clients
 
Red Hat Camel Spring Boot
 
Red Hat Service Registry
 
Red Hat Apicurio Registry
 
Red Hat Debezium
 
Red Hat Build Keycloak
 
Red Hat Optaplanner
 
Red Hat Enterprise Linux Ai
 
Red Hat Jboss Fuse
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Jbosseapxp
 
Red Hat Openshift Ai
 
Red Hat Jboss Enterprise Bpms Platform
 
Red Hat Single Sign On
 
Red Hat Amq Streams
 
Red Hat Camel Quarkus
 
Red Hat Jboss Data Grid
 
Red Hat Satellite
 
Red Hat Apache Camel Spring Boot
 

Affected Versions

netty: Red Hat Cryostat 4 on RHEL 9: Red Hat Cryostat 4 on RHEL 9: Red Hat Cryostat 4 on RHEL 9: Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16: Red Hat build of Quarkus 3.27.4: Red Hat build of Quarkus 3.33.2: Red Hat OpenShift AI 2.25: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.28: Red Hat OpenShift Dev Spaces 3.29: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat OpenShift Serverless: Red Hat AMQ Broker 7: Red Hat AMQ Clients: Red Hat build of Apache Camel 4 for Quarkus 3: Red Hat build of Apicurio Registry 2: Red Hat build of Apicurio Registry 3: Red Hat build of Debezium 3: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat build of OptaPlanner 8: Red Hat Data Grid 8: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Fuse 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat Process Automation 7: Red Hat Satellite 6: Red Hat Satellite 6: Red Hat Single Sign-On 7: Red Hat streams for Apache Kafka 2: Red Hat streams for Apache Kafka 3:

Exploit Probability

EPSS
0.41%
Percentile
32.42%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.