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Vulnerability · Published Aug 17, 2026 · Assigned by redhat

CVE-2026-66795Managedcluster-import-controller: csr auto-approver does not validate certificate subject or signername (spoke→hub cluster-admin)

Critical 9.9

In plain English

A critical-severity improper certificate validation in multicluster engine for Kubernetes 2.10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)9.9Critical
Exploit odds (30 days)0.5%top 57.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
Red Hat multicluster engine for Kubernetes 2.10 see references
Red Hat multicluster engine for Kubernetes 2.11 see references
Red Hat multicluster engine for Kubernetes 2.17 see references
Red Hat multicluster engine for Kubernetes 2.6 see references
Red Hat multicluster engine for Kubernetes 2.8 see references
Red Hat multicluster engine for Kubernetes 2.9 see references

Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References