EUVD-2026-63800
GHSA-q3cg-8r2r-6g4g
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain tenant credentials with ClusterClaim RBAC
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DeliveryDiscover target ManagedCluster namespace name
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ExploitCreate ClusterClaim with crafted spec.namespace
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ExecutionDelete the ClusterClaim to trigger controller
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PersistController deletes targeted ManagedCluster without ownership check
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ImpactAvailability DoS on victim cluster
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service Server-side security enforcement
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| Exploitation Conditions | The attacker must be an authenticated tenant in the MCE hub cluster with Kubernetes RBAC permissions to both create and delete ClusterClaim resources (PR:L). This is a standard permission granted to users who legitimately manage cluster claims. No elevated privileges, no special product features, and no non-default configuration are required - the vulnerability exists in the default clusterclaims-controller behavior. Exploitation is limited by the requirement for valid tenant credentials (preventing anonymous external attackers) and knowledge of target ManagedCluster namespace names (which may be discoverable via list permissions on ManagedCluster or Namespace objects). Environments where all ClusterClaim users are fully trusted administrators face negligible realistic risk. |
| Impact | The CVSS 3.1 score of 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H) accurately reflects a meaningful but bounded threat: network-accessible, low-complexity, low-privilege exploitation with cross-tenant scope and high availability impact. No EPSS score was provided in the source data, so exploitation probability cannot be quantified numerically. No CISA KEV listing and no public POC have been identified, suggesting this has not yet been weaponized broadly. The real-world risk is significant in multi-tenant MCE deployments where untrusted or compromised tenants share a hub - a single tenant account can trigger a hub-wide denial of service by deleting the local-cluster or cascading through all ManagedClusters. Single-tenant or internally-trusted deployments face substantially lower risk. The missing data point is a specific patched version; remediation urgency cannot be precisely scoped without a confirmed fix release from Red Hat. |
| Exploit ScenarioDerived | An authenticated tenant with standard ClusterClaim permissions creates a ClusterClaim resource with the spec.namespace field set to the namespace of another tenant's ManagedCluster or the hub's local-cluster namespace. When the tenant then deletes that ClusterClaim, the clusterclaims-controller - lacking an ownership check - proceeds to delete the targeted ManagedCluster, effectively deprovisioning a cluster outside the attacker's authorized scope. No public exploit code has been identified, but the attack requires only standard kubectl access and knowledge of target namespace names. |
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Alert meAnalysisAIv1 – Aug 21, 2026
Unauthorized ManagedCluster deletion in Red Hat Multicluster Engine (MCE) allows any tenant with standard ClusterClaim permissions to destroy clusters belonging to other tenants or the hub itself, including the hub's local-cluster. The clusterclaims-controller fails to verify ownership before acting on the spec.namespace field, meaning a low-privileged tenant can target arbitrary ManagedClusters by crafting that field and then deleting the ClusterClaim. No public exploit or CISA KEV listing exists at time of analysis, but the attack requires only standard tenant credentials and no special configuration, making it a realistic insider or compromised-tenant threat.
RemediationAI
No specific patched version was confirmed in the available data - the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-73267 and Bugzilla issue 2514218 should be monitored for an official fix release. Until a patch is available, the most actionable compensating control is to restrict ClusterClaim create and delete RBAC permissions to only fully trusted service accounts and administrators, removing these permissions from general-purpose tenant roles. This trade-off reduces multi-tenancy flexibility but eliminates the attack surface entirely. Additionally, audit existing ClusterClaim RBAC bindings to identify over-privileged tenants. Implementing admission webhooks that validate spec.namespace against the requesting tenant's authorized namespaces would mitigate the root cause without removing ClusterClaim functionality, though this requires custom webhook development. Do not rely on namespace-level isolation alone, as the flaw bypasses it at the controller layer.
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Technical ContextAI · show details
Red Hat Multicluster Engine for Kubernetes (cpe:2.3:a:red_hat:multicluster_engine_for_kubernetes:*:*:*:*:*:*:*:*) is the multicluster lifecycle management layer underpinning OpenShift hub clusters. The clusterclaims-controller reconciles ClusterClaim resources, which allow tenants to claim ownership of ManagedClusters. The root cause is CWE-602 (Client-Side Enforcement of Server-Side Security): the controller trusts the tenant-supplied spec.namespace field without server-side verification that the referenced namespace/cluster belongs to the requesting tenant. Because Kubernetes RBAC permits any tenant with ClusterClaim create/delete rights to supply arbitrary namespace values, the controller acts on attacker-controlled input as if it were authoritative, triggering deletion of ManagedCluster objects outside the tenant's authorized scope. The scope change (S:C in CVSS) reflects that the impact crosses tenant boundaries within the same MCE hub.
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Network-accessible Kubernetes API, no complexity beyond valid credentials (PR:L), cross-tenant scope change, and pure availability impact via unauthorized ManagedCluster deletion.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
DescriptionCVE.org
A flaw was found in the clusterclaims-controller component of multicluster engine (MCE). A tenant with standard permissions to create and delete ClusterClaim resources can exploit this by manipulating the spec.namespace field. This allows the tenant to specify and delete any ManagedCluster, including the hub's local-cluster or other tenants' clusters, due to a missing ownership check. This vulnerability can lead to a denial of service by enabling unauthorized deletion of ManagedClusters.
Executive ViewAI
Red Hat Multicluster Engine deployments face immediate risk of unauthorized cluster destruction: any low-privileged tenant with standard permissions can delete Kubernetes clusters belonging to other business units or disable hub infrastructure. This creates direct threats to service availability and business continuity across all affected organizations. Urgent access restrictions and monitoring are required pending vendor security patches.
No vendor-released patch identified at time of analysis. Interim mitigations: (1) Remove or restrict ClusterClaim permissions to only administrative roles; (2) Implement additional RBAC policies at cluster scope limiting ManagedCluster modifications; (3) Enable audit logging with real-time alerting on cluster deletion events; (4) Enforce namespace isolation policies where architecturally feasible; (5) Require approval workflows for any ClusterClaim creation or modification by tenants.
Threat Intelligence Overview
NVD
CVE.org
EPSS
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
Privilege escalation and arbitrary code execution in Red Hat's multicluster engine (MCE) for Kubernetes lets a low-privi
Privilege escalation in Red Hat's multicluster engine for Kubernetes (MCE) lets a namespace-scoped authenticated user ga
Privilege escalation in Red Hat Multicluster Engine for Kubernetes (MCE) lets a privileged service account on a managed
Authentication and authorization bypass in the cluster-proxy-addon component of Red Hat's Multicluster Engine for Kubern
Arbitrary code execution in the control plane of Red Hat Multicluster Engine for Kubernetes (HyperShift operator) is pos
Header injection in the cluster-proxy service-proxy component of Red Hat Advanced Cluster Management for Kubernetes (RHA
Improper certificate validation in Red Hat's Open Cluster Management (OCM) and Multicluster Engine for Kubernetes allows
Supply chain code injection in Red Hat Multicluster Engine for Kubernetes (mce-operator-bundle) enables arbitrary code e
Unauthorized cross-tenant cluster takeover in Red Hat Multicluster Engine (MCE) for Kubernetes allows an authenticated t
Local privilege escalation in NetworkManager's dhclient backend allows a low-privileged local user to execute arbitrary
Container privilege escalation in Red Hat Multicluster Engine for Kubernetes allows authenticated local attackers to esc
Unauthenticated REST API write access in Maestro, the messaging and resourcing component shipped with Red Hat Multiclust
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