Skip to content
Fencer Vulns
high 7.1

CVE-2026-73266 json

Clusterclaims-controller: confused deputy: tenant-controlled clusterclaim labels propagated to managedcluster, enabling cross-tenant managedclusterset join

published 2026-08-13 2 mo ago modified 2026-09-29 40 d ago also EUVD-2026-58132

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

A flaw was found in the clusterclaims-controller component of Multicluster Engine (MCE). An authenticated tenant can exploit this vulnerability by manipulating ClusterClaim labels. This allows the tenant to force a cluster to join a ManagedClusterSet belonging to another tenant. Such unauthorized access could enable the injection of policies and workloads into other tenants' clusters.

Patch / fix

  • Red Hat multicluster engine for Kubernetes 2.10 1787196014
  • Red Hat multicluster engine for Kubernetes 2.11 1787239442
  • Red Hat multicluster engine for Kubernetes 2.17 1786577950
  • Red Hat multicluster engine for Kubernetes 2.6 1787259112
  • Red Hat multicluster engine for Kubernetes 2.8 1787259059
  • Red Hat multicluster engine for Kubernetes 2.9 1787195995

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-73266 updated cvss 7.1

clusterclaims-controller: Confused deputy: tenant-controlled ClusterClaim labels propagated to ManagedCluster, enabling cross-tenant ManagedClusterSet join

  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/clusterclaims-controller-rhel9 1787259112
    fixed: vendor fix RHSA-2026:59579
  • Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/clusterclaims-controller-rhel9 1787259059
    fixed: vendor fix RHSA-2026:59558
  • Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/clusterclaims-controller-rhel9 1787195995
    fixed: vendor fix RHSA-2026:59559
  • Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/clusterclaims-controller-rhel9 1787196014
    fixed: vendor fix RHSA-2026:59557
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/clusterclaims-controller-rhel9 1787239442
    fixed: vendor fix RHSA-2026:59556
  • Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/clusterclaims-controller-rhel9 1786577950
    fixed: vendor fix RHSA-2026:59593
  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/hive-rhel9 1787291123, multicluster-engine/work-rhel9 1787263188, multicluster-engine/discovery-rhel9 1787263531, multicluster-engine/placement-rhel9 1787260699, multicluster-engine/console-mce-rhel9 1787264250, multicluster-engine/must-gather-rhel9 1787264198, +20 more Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/hive-rhel9 1787291250, multicluster-engine/work-rhel9 1787259113, multicluster-engine/discovery-rhel9 1787259074, multicluster-engine/placement-rhel9 1787259108, multicluster-engine/console-mce-rhel9 1787259048, multicluster-engine/must-gather-rhel9 1787258992, +20 more Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/hive-rhel9 1787205132, multicluster-engine/work-rhel9 1786933545, multicluster-engine/discovery-rhel9 1786658519, multicluster-engine/placement-rhel9 1786491555, multicluster-engine/console-mce-rhel9 1787079359, multicluster-engine/must-gather-rhel9 1786837240, +23 more Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/hive-rhel9 1787205371, multicluster-engine/work-rhel9 1786933256, multicluster-engine/discovery-rhel9 1787071404, multicluster-engine/placement-rhel9 1786548467, multicluster-engine/console-mce-rhel9 1787079364, multicluster-engine/must-gather-rhel9 1786548899, +24 more Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/hive-rhel9 1787291933, multicluster-engine/work-rhel9 1786907276, multicluster-engine/discovery-rhel9 1786911975, multicluster-engine/placement-rhel9 1786911984, multicluster-engine/console-mce-rhel9 1787065052, multicluster-engine/must-gather-rhel9 1786911926, +25 more Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/hive-rhel9 1787033495, multicluster-engine/work-rhel9 1786933423, multicluster-engine/maestro-rhel9 1786985023, multicluster-engine/discovery-rhel9 1786681989, multicluster-engine/placement-rhel9 1786983381, multicluster-engine/console-mce-rhel9 1786668856, +28 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Affected products

  • Red Hat multicluster engine for Kubernetes 2.10
  • Red Hat multicluster engine for Kubernetes 2.11
  • Red Hat multicluster engine for Kubernetes 2.17
  • Red Hat multicluster engine for Kubernetes 2.6
  • Red Hat multicluster engine for Kubernetes 2.8
  • Red Hat multicluster engine for Kubernetes 2.9

Classification

Weakness
  • CWE-441 Unintended Proxy or Intermediary

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.