High severity · published Apr 22, 2026
CVE-2026-40542
Apache HttpClient: SCRAM-SHA-256 mutual authentication bypass may cause the client to accept authentication without proper mutual authentication verification
7.3
CVSS
0.5%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AH
Apache HttpClient · Apache Software Foundation
5.6 before 5.6.1 · source: vendor
HT
Httpclient · Apache
5.6 · source: NVD
OD
OpenShift Developer Tools and Services · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.12 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.13 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.14 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.15 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.16 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.17 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.18 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.19 · Red Hat
All versions, or not specified · source: CISA
OD
OpenShift Developer Tools and Services 4.20 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40542
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40542
Mailing List
https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97
Mailing List
http://www.openwall.com/lists/oss-security/2026/04/22/5
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:60239
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:60246
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:60247
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:60248