Red Hat disclosed CVE-2026-73269, a critical privilege-escalation flaw in the cluster-curator-controller component used by OpenShift Multicluster Engine for Kubernetes. The bug allows a tenant with only namespace-level access to create a crafted ClusterCurator resource whose metadata.name differs from metadata.namespace, triggering the controller to create a cluster-scoped ClusterRoleBinding and, in some cases, a RoleBinding in an arbitrary namespace. Those bindings can attach the tenant’s namespace-local cluster-installer service account to the powerful curator role, effectively breaking namespace isolation.
Successful exploitation can elevate a local tenant to cluster-wide privileges, including access to and manipulation of secrets, management of cluster actions, and deletion of hosted clusters or node pools. The issue carries a CVSS 3.1 score of 9.9 and affects multicluster-engine/cluster-curator-controller-rhel9. Red Hat advised organizations to apply vendor fixes and reduce exposure by restricting creation of ClusterCurator resources through RBAC, enforcing matching metadata.name and metadata.namespace with an admission controller, and reviewing permissions that allow creation of cluster-scoped resources.

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Red Hat last modified the CVE-2026-73269 record, maintaining the affected product details, severity information, and mitigation guidance. The entry still indicated no erratum was listed for the affected package.
Red Hat Bugzilla recorded issue 2514220 describing how a ClusterCurator resource with mismatched metadata.name and metadata.namespace can cause ApplyRBACHypershift to create a RoleBinding in an arbitrary namespace and a cluster-scoped ClusterRoleBinding. The report states this can bind a namespace-local service account to the curator ClusterRole and escalate access to cluster-wide privileges.
Red Hat published CVE-2026-73269 for a privilege-escalation flaw in the Multicluster Engine cluster-curator-controller. The issue allows a tenant with namespace-level access to craft a ClusterCurator resource that triggers creation of bindings granting cluster-wide privileges.
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