Bug 2514217 (CVE-2026-73266) - CVE-2026-73266 clusterclaims-controller: Confused deputy: tenant-controlled ClusterClaim labels propagated to ManagedCluster, enabling cross-tenant ManagedClusterSet join
Summary: CVE-2026-73266 clusterclaims-controller: Confused deputy: tenant-controlled C...
Keywords:
Status: NEW
Alias: CVE-2026-73266
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-11 17:18 UTC by OSIDB Bzimport
Modified: 2026-09-02 16:57 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-08-11 17:18:32 UTC 
A flaw was found in the clusterclaims-controller component of multicluster engine (MCE). The createManagedCluster() function copies all tenant-controlled ClusterClaim labels onto the cluster-scoped ManagedCluster object without filtering, and setClusterSetLabel() preserves a tenant-supplied clusterset label. Combined with the controller's ClusterRole granting managedclustersets/join:create without resourceNames restrictions, a tenant can set a ClusterClaim label to join an arbitrary ManagedClusterSet belonging to another tenant. This confused deputy attack allows cross-tenant ManagedClusterSet join, potentially enabling policy and workload injection into victim clusters selected by Placement resources.

Upstream repo: https://github.com/stolostron/clusterclaims-controller
Audited commit: 89615dc8ce2de4aac192bf0289ab1a345947f28c
Jira tracker: ACM-38720
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