Omni manages Kubernetes on bare metal, virtual machines, or in a cloud. From 1.3.0 until 1.6.6 and 1.7.3, importing a standalone Talos cluster creates an ImportedClusterSecrets resource containing the cluster's complete CA secrets bundle. The access rules in internal/backend/runtime/omni/state_access.go allow an authenticated user with the Reader role to retrieve the resource through ResourceService if the importing actor has not rotated those secrets, exposing Kubernetes, Talos, and etcd CA private keys plus the service-account key. The Kubernetes CA private key permits certificate signing for privileged identities such as system:masters and provides control of the imported cluster outside Omni's authorization boundary, including its workloads, credentials, and secrets. This issue is fixed in versions 1.6.6 and 1.7.3.

Affected: Go: github.com/siderolabs/omni

## Summary

Omni supports importing standalone Talos clusters.

During this process, an ImportedClusterSecrets resource is created, which contains the full CA secrets bundle for the cluster being imported.

If these secrets are not rotated by the importing actor, an authenticated Omni user with Reader access can read this resource and gain full access to the Talos, Kubernetes and etcd APIs of the cluster.

## Severity

- **Attack Vector:** Adjacent: the attacker needs to be in the same network to be able to access Talos/Kubernetes APIs with the compromised keys. - **Attack Complexity:** High: the attacker needs a deep understanding of Omni's internals. The resource is only created for imported clusters, and is normally not represented to users via any high-level API. - **Privileges Required:** Low: the role `Reader` is sufficient for the attacker to be able to read an imported cluster's secrets. - **User Interaction:** Required: another user must have imported a cluster to Omni for this vulnerability to exist. - **Scope:** Changed: the leaked CA private keys let an attacker directly get full control on Kubernetes or Talos, beyond the limitations enforced by Omni. - **Confidentiality Impact:** High: full cluster CA private keys (Kubernetes, Talos, etcd, service account) are exposed. - **Integrity Impact:** High: with the CA keys the attacker has full control on Kubernetes and Talos of the compromised (imported) cluster, and modify the workloads on it. - **Availability Impact:…