CVE-2026-40542 — HIGH (7.3)

Vulnerability Description

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.

CVSS Score

7.3

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

LOW

Integrity

LOW

Availability

LOW

Affected Products

Vendor	Product	Versions
Apache	Httpclient	5.6

Related Weaknesses (CWE)

CWE-304

References

https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97Mailing ListVendor Advisory
http://www.openwall.com/lists/oss-security/2026/04/22/5Mailing ListThird Party Advisory

FAQ

What is CVE-2026-40542?

CVE-2026-40542 is a vulnerability with a CVSS score of 7.3 (HIGH). 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 ...

How severe is CVE-2026-40542?

CVE-2026-40542 has been rated HIGH with a CVSS base score of 7.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-40542?

Check the references section above for vendor advisories and patch information. Affected products include: Apache Httpclient.