Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.1%
exploitation probability
0.1%top 96% of all CVEs
observed exploitation
nono source reports it
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: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 KubernetesRed Hat · multicluster engine for Kubernetes 2.1Red Hat · multicluster engine for Kubernetes 2.11Red Hat · multicluster engine for Kubernetes 2.6Red Hat · multicluster engine for Kubernetes 2.8Red Hat · multicluster engine for Kubernetes 2.9References
https://access.redhat.com/errata/RHSA-2026:11414https://access.redhat.com/errata/RHSA-2026:13542https://access.redhat.com/errata/RHSA-2026:13853https://access.redhat.com/errata/RHSA-2026:8218https://access.redhat.com/errata/RHSA-2026:9848https://access.redhat.com/security/cve/CVE-2026-4740https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/https://bugzilla.redhat.com/show_bug.cgi?id=2450590https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json