How severe is CVE-2026-40542?

CVE-2026-40542 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-40542 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40542?

CVE-2026-40542 affects Apache Httpclient. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40542?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-40542 have an EU (EUVD) identifier?

Yes. CVE-2026-40542 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24630.

When was CVE-2026-40542 published?

CVE-2026-40542 was published on 2026-04-22 and last updated on 2026-06-30.

CVE-2026-40542

CVE-2026-40542 is a high-severity vulnerability in Apache Httpclient with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-304.

Key facts

Severity: High (CVSS 3.x base score 7.3)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24630
Weakness: CWE-304
Affected product: Apache Httpclient
Published: 2026-04-22
Last modified: 2026-06-30

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.

Frequently asked questions

What is CVE-2026-40542?: 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.
How severe is CVE-2026-40542?: CVE-2026-40542 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-40542 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40542?: CVE-2026-40542 affects Apache Httpclient. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40542?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40542 have an EU (EUVD) identifier?: Yes. CVE-2026-40542 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24630.
When was CVE-2026-40542 published?: CVE-2026-40542 was published on 2026-04-22 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:apache:httpclient:5.6:-:*:*:*:*:*:*

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