Sidero Omni: Reader role can read the full CA secrets bundle of an imported Talos cluster

Impact

Importing a standalone Talos cluster stores the cluster's complete CA secrets bundle in an ImportedClusterSecrets resource, and the access rules let any authenticated user with the Reader role fetch it through ResourceService when the importing actor has not rotated the secrets. That hands over the Kubernetes, Talos and etcd CA private keys plus the service-account key. With the Kubernetes CA key an attacker signs a certificate for system:masters and owns the imported cluster outside Omni's authorization boundary - every workload on it, and every credential and secret it holds. For an operator running GPU clusters under Omni, a low-privilege console account becomes full cluster admin on any imported cluster.

Who can reach it

Any authenticated Omni user holding the Reader role who can call ResourceService. Affects imported standalone Talos clusters whose secrets were never rotated after import.

What to do

Upgrade Omni to 1.6.6 or 1.7.3. Versions from 1.3.0 up to those releases are affected. Upgrading alone does not undo prior exposure: rotate the CA secrets of any cluster imported before the upgrade, since the keys may already have been read. This is a management-plane service upgrade, not a fleet-wide node action.

References

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