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CVE-2026-4740

Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation

Published: Apr 7, 2026Updated: Apr 28, 2026 Sources: CVE List NVDCWE-295
NVD MITRE
8.2CVSSHIGH
EPSS Score
0.1%
Top 98.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster.

CVSS Vector Breakdown

AV:LAC:LPR:HUI:NS:CC:HI:HA:H
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:HPrivileges Required
High
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-295

Affected Products

advanced cluster management for kubernetesredhat
On-prem
Operating Systems / linux-distro
Multicluster Engine for KubernetesRed Hat
On-prem
Operating Systems / linux-distro
redhatcommercialUSOperating Systemsaka red hat
red hatcommercialUSOperating Systemsaka red hat

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://access.redhat.com/security/cve/CVE-2026-4740
access.redhat.com
https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/
blog.arfevrier.fr
https://bugzilla.redhat.com/show_bug.cgi?id=2450590
bugzilla.redhat.com

Timeline

Published
Apr 7, 2026
Last Updated
Apr 28, 2026

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