Advisory severityHigh7.3Apache Software Foundation

High [CVE-2026-40542] Apache HttpClient: SCRAM-SHA-256 mutual authentication bypass may cause the client to accept authentication without proper mutual authentication verification

This high-severity Apache Software Foundation advisory covers CVE-2026-40542 affecting Apache HttpClient.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-40542 Source published Apr 22, 2026Source updated Sep 9, 2026

VulniPulse record published Jul 7, 2026Record updated Sep 9, 2026

CVE-2026-40542

Affected products & platforms

Apache Software FoundationUnclassified

Open source advisory

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Summary

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.

Affected versions

Apache HttpClient 5.6 before 5.6.1

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

Fixed versions

5.6.1

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Users are recommended to upgrade to version 5.6.1, which fixes this issue.

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

Sources

Official and corroborating records used to build this advisory.

CVE.org CNA affected-product recordCVE.org
Structured CNA affected[] data independently confirmed the affected product scope; native advisory content remains authoritative.
CVE Program
NVD discovery recordNVD
Independent discovery and scoring cross-reference. Vendor remediation guidance takes precedence. Discovered from the machine-readable feed https://services.nvd.nist.gov/rest/json/cves/2.0; this link opens the NVD record for CVE-2026-40542 instead of the raw feed document.
NIST National Vulnerability Database

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-40542NVD CVE.org MITRE

Official resources

ASF Security — reporting & CVE process
Official documentation
The Apache Software Foundation's official security page: how ASF CVEs are published and where each project's advisories live.
Apache project downloads (fixed releases)
Official documentation
Official ASF download tree — fetch the fixed release named in this advisory from the project's directory.

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