CVE-2026-40542: Httpclient5 Apache HttpClient Accepts SCRAM-SHA-256 Authentication Vulnerability

HIGH
Advisory Identifier: GHSA-v468-qcjx-r72w
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CVSS 7.3
CWE-304
Published
Advisory Summary

CVE-2026-40542 is a HIGH (CVSS 7.3) apache httpclient accepts scram-sha-256 authentication vulnerability (CWE-304: Missing Critical Step in Authentication) affecting Httpclient5 libraries in the Maven ecosystem. The issue involves apache httpclient accepts scram-sha-256 authentication without proper mutual authentication verification. Remediation is available by upgrading affected packages to version 5.6.1.

CVE-2026-40542 at a Glance

CVE Identifier CVE-2026-40542
GHSA Identifier GHSA-v468-qcjx-r72w
Severity HIGH
CVSS v3.1 Base Score 7.3
CWE Classification CWE-304: Missing Critical Step in Authentication
Affected Product Httpclient5
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-40542

To remediate this vulnerability, upgrade all affected Httpclient5 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.httpcomponents.client5:httpclient5 fixed: 5.6.1 
<dependency>
    <groupId>org.apache.httpcomponents.client5</groupId>
    <artifactId>httpclient5</artifactId>
    <version>5.6.1</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-40542, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5

Analyze the terminal output to locate any version of Httpclient5 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.6.1), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5 command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-304: Missing Critical Step in Authentication, where the product implements an authentication technique, but it skips a step that weakens the technique. In Httpclient5, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-40542 Affected Httpclient5 Versions

1 component(s)
Fixed Versions:
5.6.1
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.httpcomponents.client5:httpclient5
maven/org.apache.httpcomponents.client5/httpclient5
Maven
≥ 5.6-alpha1
< 5.6.1
5.6.1

References

NVD — CVE-2026-40542 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40542
Security Fix Commit FIX COMMIT
https://github.com/apache/httpcomponents-client/commit/726eac2323d370435d8afca1e0540aa099927f18
Httpclient5 Source Repository REPOSITORY
https://github.com/apache/httpcomponents-client
lists.apache.org/thread/tfmgv86xr0z1... WEB
https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97
Httpclient5 Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/04/22/5

Frequently Asked Questions

What is CVE-2026-40542?
CVE-2026-40542 is a security vulnerability in Httpclient5 involving Apache HttpClient accepts SCRAM-SHA-256 authentication without proper mutual authentication verification under CWE-304: Missing Critical Step in Authentication.
Which Httpclient5 versions are affected?
Affected versions include releases prior to 5.6.1 across affected packages: org.apache.httpcomponents.client5:httpclient5.
What version fixes CVE-2026-40542?
Upgrading to 5.6.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is httpclient5 affected?
Yes, org.apache.httpcomponents.client5:httpclient5 is affected in releases prior to 5.6.1. Upgrade your dependency to 5.6.1 or later.
What is the CVSS score of CVE-2026-40542?
CVE-2026-40542 has a CVSS v3.1 base score of 7.3 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2026-40542?
CVE-2026-40542 is classified under CWE-304: Missing Critical Step in Authentication (The product implements an authentication technique, but it skips a step that weakens the technique.).
How can I check Maven dependencies for CVE-2026-40542?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-v468-qcjx-r72w",
  "modified" : "2026-04-29T20:52:54Z",
  "published" : "2026-04-22T09:31:31Z",
  "aliases" : [ "CVE-2026-40542" ],
  "summary" : "Apache HttpClient accepts SCRAM-SHA-256 authentication without proper mutual authentication verification",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.httpcomponents.client5:httpclient5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.6-alpha1"
      }, {
        "fixed" : "5.6.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40542"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/httpcomponents-client/commit/726eac2323d370435d8afca1e0540aa099927f18"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/httpcomponents-client"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/04/22/5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-304" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-29T20:52:54Z",
    "nvd_published_at" : "2026-04-22T08:16:12Z"
  }
}