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HttpclientApplication · Apache

CVE-2026-40542

HIGH · 7.3 CVSS v3.1 Published 2026-04-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
82/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache HttpClient 5.6 has a vulnerability in SCRAM-SHA-256 authentication where the client fails to properly verify mutual authentication from the server. This allows a man-in-the-middle attacker to impersonate the server during the authentication handshake, bypassing the mutual authentication step that proves the server's identity to the client.

MitigationUpgrade Apache HttpClient to version 5.6.1 or later to obtain the patched implementation that properly verifies mutual authentication in SCRAM-SHA-256.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
HttpclientApplication
Affected:= 5.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Apache HttpClient version in use
    Check your project's dependency management file (Maven pom.xml, Gradle build.gradle) or the JAR file name for 'httpclient' version 5.6. If using a fat JAR or embedded library, search your codebase for imports from 'org.apache.hc.client5.http' and inspect the library on the classpath.
    Affected if The version listed or loaded is exactly 5.6 (no patch version)
  2. Determine if SCRAM-SHA-256 authentication is configured
    Search your codebase and configuration files for SCRAM-SHA-256 or SCRAM mechanism configuration. Look for 'SCRAM-SHA-256', 'SCRAM', or 'SCRAMClientManager' in configuration classes, property files, or authentication setup code.
    Affected if SCRAM-SHA-256 is explicitly configured as the authentication mechanism for any HTTP client
  3. Verify the client uses default SCRAM authentication settings
    Inspect the HttpClient builder or configuration where SCRAM-SHA-256 is set up. Check whether custom implementations or overrides are applied to the mutual authentication verification step.
    Affected if Using default HttpClient SCRAM configuration with no custom verification logic overrides

You are affected if you have Apache HttpClient version 5.6 with SCRAM-SHA-256 authentication enabled in your environment.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Apache HttpClient to version 5.6.1 or later to obtain the patched implementation that properly verifies mutual authentication in SCRAM-SHA-256.

Recommended fix High confidence

Apache HttpClient 5.6.1

  1. Identify all project dependencies that reference Apache HttpClient 5.6 (e.g., check pom.xml, build.gradle, requirements.txt, or similar dependency management files)
  2. Update the HttpClient dependency version from 5.6 to 5.6.1
  3. For Maven projects, update the dependency in pom.xml: change org.apache.httpcomponents.client5:httpclient5 from 5.6 to 5.6.1
  4. For Gradle projects, update the dependency: implementation 'org.apache.httpcomponents.client5:httpclient5:5.6.1'
  5. For other build systems, update to the corresponding 5.6.1 artifact
  6. Run dependency resolution to verify the correct version is pulled (e.g., mvn dependency:tree or gradle dependencies)
  7. Rebuild the project and run tests to ensure the upgrade does not break existing functionality
Caveat Point releases in the 5.x line typically maintain backward compatibility; minimal risk expected

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Httpclient Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40542 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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