EUVD-2026-53293
GHSA-f7c4-3r82-969w
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate as namespace-scoped tenant admin
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DeliveryCreate namespaced ClusterCurator resource
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ExploitController mints cluster-admin ServiceAccount token
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ExecutionUse token to assume cluster-admin
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ImpactTake full control of cluster
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V8 - Authorization Privilege assignment review
|
| Exploitation Conditions | Exploitation requires the attacker to already hold namespace-scoped tenant-administrator privileges on a cluster running Multicluster Engine, and requires that they be able to create a ClusterCurator custom resource in a namespace they control - creating that namespaced ClusterCurator is the specific triggering action that causes the controller to mint a cluster-admin ServiceAccount token. Limiting factors: it is not exploitable by unauthenticated or fully unprivileged users (per PR in the CVSS vector, authentication and an existing tenant-admin role are needed), and it is only relevant to multi-tenant MCE/ACM deployments where untrusted parties are granted namespace-admin rights - single-tenant or fully-trusted-admin clusters face no additional exposure since those users could already act cluster-wide. |
| Impact | The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H, 9.1 Critical) indicates network-reachable, low-complexity exploitation with a changed scope and full CIA impact, but it requires existing privileges (PR:H) - the attacker must already be a tenant/namespace administrator, so this is an insider or post-compromise escalation rather than an anonymous internet attack. Note a modeling tension: the description frames the attacker as a namespace-scoped tenant (a comparatively limited role), which is arguably PR:L, yet Red Hat assigned PR:H; either way authentication and a pre-existing tenant role are required, so this is not exploitable by an unauthenticated outsider. No EPSS score, KEV entry, or SSVC decision data was provided; there is no public exploit identified at time of analysis. Real-world priority is high specifically for multi-tenant MCE/ACM deployments where untrusted tenants hold namespace-admin rights, and correspondingly lower for single-tenant clusters where all namespace admins are already trusted with cluster access. |
| Exploit ScenarioDerived | A tenant administrator holding only namespace-scoped admin rights on a shared MCE-managed cluster creates a ClusterCurator resource in their own namespace. The controller processes it and issues the tenant a token for a cluster-admin ServiceAccount, which the tenant then uses to read all secrets, modify workloads, and take over the entire cluster. No public proof-of-concept has been identified at time of analysis. |
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Alert meAnalysisAIv1 – Aug 05, 2026
Privilege escalation in Red Hat's Multicluster Engine (MCE) for Kubernetes ClusterCurator controller allows a namespace-scoped tenant administrator to obtain cluster-wide administrative control. By creating a namespaced ClusterCurator resource, the tenant can cause the controller to mint an authentication token for a ServiceAccount holding cluster-admin authority, breaking tenant isolation. Rated CVSS 9.1 (scope-changed) by Red Hat; no public exploit identified at time of analysis and not listed in CISA KEV.
RemediationAI
No vendor-released patch version was identified in the provided data - monitor the Red Hat advisory (https://access.redhat.com/security/cve/CVE-2026-10059) and Bugzilla (https://bugzilla.redhat.com/show_bug.cgi?id=2483187) for the errata and apply the fixed MCE/ACM operator build as soon as it is published, since a corrected controller is the only complete fix. Until then, apply compensating controls: restrict who can create ClusterCurator custom resources by tightening RBAC so untrusted tenants cannot create or modify ClusterCurator objects in their namespaces (trade-off: tenants lose self-service curation/upgrade automation); avoid granting namespace-admin roles to untrusted tenants on clusters running MCE; and audit existing ServiceAccount token issuance and ClusterCurator creation events to detect abuse. If ClusterCurator-driven automation is not in use, consider disabling or scoping down the curator controller's ability to be invoked from tenant namespaces.
Affected ProductsAI
Red Hat Multicluster Engine for Kubernetes (the ClusterCurator controller component), which also underpins Red Hat Advanced Cluster Management for Kubernetes. Specific fixed and affected version ranges are not enumerated in the provided NVD data; consult the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-10059 and the tracking bug https://bugzilla.redhat.com/show_bug.cgi?id=2483187 for the authoritative affected-version list and errata. No CPE strings were supplied in the input.
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Technical ContextAI · show details
Multicluster Engine for Kubernetes is the Red Hat operator (the upstream engine behind Red Hat Advanced Cluster Management) that provisions and lifecycle-manages fleets of Kubernetes/OpenShift clusters. ClusterCurator is a custom resource and controller that orchestrates cluster provisioning, upgrade, and hook automation. The root cause maps to CWE-266 (Incorrect Privilege Assignment): the controller processes a tenant-supplied namespaced ClusterCurator in a way that lets the requester obtain a token for a highly privileged ServiceAccount, so an object a tenant is authorized to create is used as a vehicle to acquire credentials far exceeding the tenant's namespace scope. This is a classic controller confused-deputy / RBAC boundary failure where a namespaced control-plane resource influences cluster-scoped identity issuance.
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Severity by source
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Attacker is a limited namespace-scoped tenant (PR:L, not PR:H); creating one resource yields full cluster-admin, so scope changes (S:C) with total C/I/A impact.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
DescriptionCVE.org
A flaw was found in the Multicluster Engine for Kubernetes ClusterCurator controller. A tenant administrator with namespace-scoped privileges can exploit this vulnerability by creating a namespaced ClusterCurator. This action inadvertently grants the tenant administrator the ability to mint a token for a ServiceAccount with cluster-wide administrative authority. This leads to a privilege escalation, allowing the tenant administrator to gain full control over the cluster.
Articles & Coverage 1
Executive ViewAI
Red Hat Multicluster Engine (MCE) for Kubernetes contains a critical privilege escalation vulnerability (CVE-2026-10059, CVSS 9.1) that enables namespace-scoped tenant administrators to break tenant isolation and obtain cluster-wide administrative control by exploiting the ClusterCurator controller. This directly undermines multi-cluster governance and puts all workloads and data across managed clusters at risk. Organizations relying on MCE for multi-tenant or multi-cluster management must treat this as a critical containment issue requiring immediate action.
No vendor-released patch identified at time of analysis. Interim mitigations: (1) Enforce RBAC policies restricting ClusterCurator creation to cluster operators only; (2) implement namespace-level policies preventing ClusterCurator resources outside designated control namespaces; (3) enable audit logging and alerting for all ClusterCurator and ServiceAccount token APIs; (4) immediately audit and rotate all cluster-admin ServiceAccount tokens; (5) network-segment MCE control plane with restricted egress. Monitor vendor advisories continuously and apply patch immediately upon release.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
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
Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.
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