CVE-2026-40542

Name: CVE-2026-40542
Creator: NVD / NIST
Published: 2026-04-22T08:16:12.78+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.3/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2026-40542 is a high-severity vulnerability rated 7.3/10 on the CVSS scale. 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.. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.3/10

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

EPSS Probability

0.56%

42.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-304

Affected Software

Vendor	Product	Versions
Apache	Httpclient	5.6

References

https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97Mailing List, Vendor Advisory
http://www.openwall.com/lists/oss-security/2026/04/22/5Mailing List, Third Party Advisory

Timeline

Published: Apr 22, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-40542?

How severe is CVE-2026-40542?

CVE-2026-40542 has a CVSS score of 7.3/10 (HIGH severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2026-40542?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40542?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST