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VulnerabilityPublished Updated

CVE-2026-40542: Apache HttpClient · Missing Critical Step in Authentication

Affects Apache HttpClientSource CVE Database V5

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Not known to be exploited · CVSS 7.3 High : upgrade to 5.6.1 soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
7.3High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade Apache to 5.6.1.

Affected software

ProductAffectedFixed in
Apache Software FoundationApache HttpClientAffected
  • >=5.6 <5.6.1
Fixed in
  • 5.6.1
Mavenorg.apache.httpcomponents/httpclientpkg:maven/org.apache.httpcomponents/httpclientOther threatsAffected
  • =5.6
Fixed in–
MavenApache Software Foundation/org.apache.httpcomponents.client5:httpclient5pkg:maven/Apache Software Foundation/org.apache.httpcomponents.client5:httpclient5Other threatsAffected
  • >=5.6 <5.6.1
Fixed in
  • 5.6.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade Apache HttpClient from version 5.6 to 5.6.1 or later, where this vulnerability is fixed. No other mitigations are specified in the vendor advisory. Patch status is confirmed by the vendor advisory recommending upgrade to 5.6.1.

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.

References

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