Vulnerability in Red Hat Multicluster Engine For Kubernetes
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.
Vulnerability class: Improper Certificate Validation
EPSS: 0.001 (4.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Red Hat Multicluster Engine For Kubernetes
- Red Hat Multicluster Engine For Kubernetes 2.1 — versions 1776881164
- Red Hat Multicluster Engine For Kubernetes 2.10 — versions 1776881164
- Red Hat Multicluster Engine For Kubernetes 2.11 — versions 1777478390
- Red Hat Multicluster Engine For Kubernetes 2.11.0 — versions 1777478390
- Red Hat Multicluster Engine For Kubernetes 2.6 — versions 1775977180
- Red Hat Multicluster Engine For Kubernetes 2.8 — versions 1775638726
- Red Hat Multicluster Engine For Kubernetes 2.9 — versions 1776445095
- Redhat Advanced_cluster_management_for_kubernetes
Weakness classification (CWE)
References
- secalert@redhat.com (x_refsource_REDHAT, vdb-entry, Vendor Advisory)
- secalert@redhat.com (Exploit, Third Party Advisory)
- secalert@redhat.com (x_refsource_REDHAT, issue-tracking, Issue Tracking, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
Frequently asked questions
- What is CVE-2026-4740?
- CVE-2026-4740 is a high-severity vulnerability in Red Hat Multicluster Engine For Kubernetes, classified under Improper Certificate Validation. CVSS score: 8.2/10. Published 2026-04-07.
- How severe is CVE-2026-4740?
- High severity. CVSS v3 base score is 8.2 out of 10.