CVE-2026-66795

CRITICAL 9.9

Managedcluster-import-controller: csr auto-approver does not validate certificate subject or signername (spoke→hub cluster-admin)

CVSS Score

9.9

EPSS Score

0.5%

EPSS Percentile

40th

A flaw was found in the managedcluster-import-controller. The Certificate Signing Request (CSR) auto-approval logic improperly validates incoming CSRs, specifically by not inspecting the signer name or decoding the PEM-encoded x509 CSR. This vulnerability allows a privileged service account on a spoke cluster to submit a malicious CSR. Successful exploitation can lead to privilege escalation, enabling the attacker to obtain administrative credentials on the hub cluster.

CWE	CWE-295
Vendor	red hat
Product	multicluster engine for kubernetes 2.10
Published	Aug 17, 2026
Last Updated	Sep 29, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

Red Hat / multicluster engine for Kubernetes 2.10

All versions affected

Red Hat / multicluster engine for Kubernetes 2.11

All versions affected

Red Hat / multicluster engine for Kubernetes 2.17

All versions affected

Red Hat / multicluster engine for Kubernetes 2.6

All versions affected

Red Hat / multicluster engine for Kubernetes 2.8

All versions affected

Red Hat / multicluster engine for Kubernetes 2.9

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗