---
id: CVE-2026-73266
title: >-
  A flaw was found in the clusterclaims-controller component of Multicluster
  Engine (MCE)
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 Mana…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N'
cwe:
  - CWE-441
vendor: Red Hat
product: multicluster-engine/clusterclaims-controller-rhel9
affected:
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
  - multicluster-engine/clusterclaims-controller-rhel9 (all versions)
published: '2026-08-13'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T13:17:21.923'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73266'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:59556'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:59557'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:59558'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:59559'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:59579'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:59593'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-73266'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2514217'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73266.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-73266'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73266'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-18T01:25:32.223923Z'
epss: 0.00352
epssPercentile: 0.26045
ingestedAt: '2026-09-05T18:43:14.057Z'
patched:
  - multicluster_engine_for_kubernetes 2.11
  - multicluster_engine_for_kubernetes 2.17
  - multicluster_engine_for_kubernetes 2.1
  - multicluster_engine_for_kubernetes 2.6
  - multicluster_engine_for_kubernetes 2.8
  - multicluster_engine_for_kubernetes 2.9
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:59556** · Red Hat · fixed in: multicluster engine for Kubernetes 2.11 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59556)
- **RHSA-2026:59593** · Red Hat · fixed in: multicluster engine for Kubernetes 2.17 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59593)
- **RHSA-2026:59557** · Red Hat · fixed in: multicluster engine for Kubernetes 2.1 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59557)
- **RHSA-2026:59579** · Red Hat · fixed in: multicluster engine for Kubernetes 2.6 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59579)
- **RHSA-2026:59558** · Red Hat · fixed in: multicluster engine for Kubernetes 2.8 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59558)
- **RHSA-2026:59559** · Red Hat · fixed in: multicluster engine for Kubernetes 2.9 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59559)