CVE-2026-66795Network attack vector

Hub cluster-admin escalation via unvalidated CSRs

Published Aug 17, 2026 · Updated Aug 25, 2026

Privilege escalation in Red Hat multicluster engine for Kubernetes allows remote authenticated users to gain hub cluster-admin credentials. The managedcluster-import-controller auto-approver neither checks signerName nor decodes and inspects the PEM-encoded X.509 CSR subject before approval. A compromised spoke bootstrap service account is required, and approval yields administrative credentials on the hub cluster.

CVSS severity9.9
Critical
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Red Hat multicluster engine for Kubernetes allows remote authenticated users to gain hub cluster-admin credentials. The managedcluster-import-controller auto-approver neither checks signerName nor decodes and inspects the PEM-encoded X.509 CSR subject before approval. A compromised spoke bootstrap service account is required, and approval yields administrative credentials on the hub cluster.

The record

CVE
CVE-2026-66795
Published
Aug 17, 2026
Updated
Aug 25, 2026
Vendor
389 Directory Server
Product
multicluster engine for Kubernetes
Classifications
CWE-295, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 17, 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

9.9Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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.

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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-295Improper Certificate Validation
T1068Exploitation for Privilege Escalation

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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