CVE-2026-4740

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 v3 8.2 HIGH

8.2^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.5 / Impact : 6.0

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://access.redhat.com/errata/RHSA-2026:11414
https://access.redhat.com/errata/RHSA-2026:13542
https://access.redhat.com/errata/RHSA-2026:13853
https://access.redhat.com/errata/RHSA-2026:8218
https://access.redhat.com/errata/RHSA-2026:9848
https://access.redhat.com/security/cve/CVE-2026-4740	Vendor Advisory
https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/	Exploit Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2450590	Issue Tracking Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:11414
https://access.redhat.com/errata/RHSA-2026:13542
https://access.redhat.com/errata/RHSA-2026:13853
https://access.redhat.com/errata/RHSA-2026:8218
https://access.redhat.com/errata/RHSA-2026:9848
https://access.redhat.com/security/cve/CVE-2026-4740	Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2450590	Issue Tracking Vendor Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json

Configurations

Configuration 1 (hide)

cpe:2.3:a:redhat:advanced_cluster_management_for_kubernetes:-:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-07 15:17

Updated : 2026-09-08 12:16

NVD link : CVE-2026-4740

Mitre link : CVE-2026-4740

CVE.ORG link : CVE-2026-4740

JSON object : View

Products Affected

redhat

advanced_cluster_management_for_kubernetes

CWE

CWE-295

Improper Certificate Validation

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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."}], "lastModified": "2026-09-08T12:16:54.783", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:redhat:advanced_cluster_management_for_kubernetes:-:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7301AD20-0188-463F-9386-9D878AD3A542"}], "operator": "OR"}]}], "sourceIdentifier": "secalert@redhat.com"}