Apache HttpClient 5.6 Auth Bypass SCRAM-SHA-256 (CVE-2026-40542)
CVE-2026-40542 Published on April 22, 2026

Apache HttpClient: SCRAM-SHA-256 mutual authentication bypass may cause the client to accept authentication without proper mutual authentication verification
Missing critical step in authentication in Apache HttpClient 5.6 allows an attacker to cause the client to accept SCRAM-SHA-256 authentication without proper mutual authentication verification. Users are recommended to upgrade to version 5.6.1, which fixes this issue.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-40542 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.

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

Weakness Types

Missing Critical Step in Authentication

The software implements an authentication technique, but it skips a step that weakens the technique. Authentication techniques should follow the algorithms that define them exactly, otherwise authentication can be bypassed or more easily subjected to brute force attacks.

Missing Cryptographic Step

The product does not implement a required step in a cryptographic algorithm, resulting in weaker encryption than advertised by the algorithm.


Products Associated with CVE-2026-40542

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-40542 are published in these products:

Apache Httpclient
 
Red Hat Ocp Tools
 
Red Hat Cryostat
 
Red Hat Migration Toolkit Applications
 
Red Hat Serverless
 
Red Hat Amq Broker
 
Red Hat Amq Clients
 
Red Hat Apache Camel Hawtio
 
Red Hat Camel Quarkus
 
Red Hat Camel Spring Boot
 
Red Hat Service Registry
 
Red Hat Apicurio Registry
 
Red Hat Debezium
 
Red Hat Optaplanner
 
Red Hat Quarkus
 
Red Hat Certificate System
 
Red Hat Jboss Data Grid
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Jboss Fuse
 
Red Hat Jboss Core Services
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Jbosseapxp
 
Red Hat Jboss Enterprise Web Server
 
Red Hat Lightspeed For Runtimes
 
Red Hat Offline Knowledge Portal
 
Red Hat Openshift Ai
 
Red Hat Openshift Devspaces
 
Red Hat Jboss Enterprise Bpms Platform
 
Red Hat Satellite
 
Red Hat Single Sign On
 
Red Hat Amq Streams
 

Affected Versions

Apache Software Foundation Apache HttpClient: Red Hat Cryostat 4: Red Hat Migration Toolkit for Applications 8: Red Hat Migration Toolkit for Applications 8: Red Hat OpenShift Developer Tools and Services: Red Hat OpenShift Developer Tools and Services: Red Hat OpenShift Developer Tools and Services: Red Hat OpenShift Developer Tools and Services: 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 Apache Camel 4 for Quarkus 3: Red Hat build of Apache Camel for Spring Boot 4: Red Hat build of Apache Camel for Spring Boot 4: Red Hat build of Apache Camel - HawtIO 4: Red Hat build of Apicurio Registry 2: Red Hat build of Apicurio Registry 3: Red Hat build of Debezium 3: Red Hat build of OptaPlanner 8: Red Hat build of Quarkus: Red Hat Certificate System 10: Red Hat Data Grid 8: Red Hat Data Grid 8: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Fuse 7: Red Hat Fuse 7: Red Hat Fuse 7: Red Hat Fuse 7: Red Hat JBoss Core Services: Red Hat JBoss Core Services: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat JBoss Web Server 5: Red Hat JBoss Web Server 5: Red Hat JBoss Web Server 6: Red Hat Lightspeed for Runtimes Operator: Red Hat Offline Knowledge Portal: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift Dev Spaces: Red Hat OpenShift Dev Spaces: Red Hat Process Automation 7: Red Hat Satellite 6: Red Hat Satellite 6: Red Hat Satellite 6: 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
0.56%
Percentile
42.24%

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.