CVE-2026-73266Network attack vector

Cross-tenant cluster takeover via unfiltered label propagation

Published Aug 13, 2026 · Updated Aug 25, 2026

Authorization bypass in Red Hat multicluster engine for Kubernetes allows remote authenticated users to control other tenants' clusters. The clusterclaims-controller copies arbitrary tenant-controlled ClusterClaim labels onto the corresponding ManagedCluster without restricting ManagedClusterSet membership labels. A tenant able to modify ClusterClaims can join a cluster to another tenant's ManagedClusterSet, enabling policy and workload injection there.

CVSS severity7.1
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Red Hat multicluster engine for Kubernetes allows remote authenticated users to control other tenants' clusters. The clusterclaims-controller copies arbitrary tenant-controlled ClusterClaim labels onto the corresponding ManagedCluster without restricting ManagedClusterSet membership labels. A tenant able to modify ClusterClaims can join a cluster to another tenant's ManagedClusterSet, enabling policy and workload injection there.

The record

CVE
CVE-2026-73266
Published
Aug 13, 2026
Updated
Aug 25, 2026
Vendor
389 Directory Server
Product
multicluster engine for Kubernetes
Classifications
CWE-441, T1610
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

389 Directory Server · multicluster engine for KubernetesAffected versions are unavailable in this record.

Published CVSS scores

7.1Red HatCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-441Unintended Proxy or Intermediary ('Confused Deputy')
T1610Deploy Container

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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