9.9Critical
CVE-2026-66795Managedcluster-import-controller: csr auto-approver does not validate certificate subject or signername (spoke→hub cluster-admin)
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.
Weakness (CWE):
CWE-295
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| multicluster engine | 2.10 | — | |
| multicluster engine | 2.11 | — | |
| multicluster engine | 2.17 | — | |
| multicluster engine | 2.6 | — | |
| multicluster engine | 2.8 | — | |
| multicluster engine | 2.9 | — | |
| Red Hat | multicluster engine for Kubernetes 2.10 | all versions | |
| Red Hat | multicluster engine for Kubernetes 2.11 | all versions | |
| Red Hat | multicluster engine for Kubernetes 2.17 | all versions | |
| Red Hat | multicluster engine for Kubernetes 2.6 | all versions | |
| Red Hat | multicluster engine for Kubernetes 2.8 | all versions | |
| Red Hat | multicluster engine for Kubernetes 2.9 | all versions |
References and patches
- RHSA-2026:59556 vendor-advisory
- RHSA-2026:59557 vendor-advisory
- RHSA-2026:59558 vendor-advisory
- RHSA-2026:59559 vendor-advisory
- RHSA-2026:59579 vendor-advisory
- RHSA-2026:59593 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-66795 vdb-entry
- RHBZ#2507540 issue-tracking