External Secrets Operator: BeyondTrust provider reads referenced Secrets across namespaces without validation

Impact

In versions 0.10.1 through 0.19.2 the BeyondTrust provider fetched Kubernetes Secrets directly without checking the namespace context or whether the store was a namespaced SecretStore or a ClusterSecretStore. A tenant who can create a SecretStore in their own namespace can therefore point it at a Secret in someone else's namespace and have the operator hand the value back. On a multi-tenant GPU cluster that breaks the namespace boundary teams rely on: registry pull secrets, object-store keys for shared checkpoint buckets, and scheduler or monitoring credentials all become readable by any tenant allowed to define a secret store. Confidentiality only - the flaw does not let the attacker write secrets - but it is enough to pivot into whatever those credentials unlock.

Who can reach it

Any user with permission to create or edit SecretStore resources in a namespace on a cluster where the BeyondTrust provider is enabled. Authenticated namespace-level access is required; no cluster-admin.

What to do

Upgrade External Secrets Operator to 0.20.0 or later, where the provider uses resolvers.SecretKeyRef and only permits cross-namespace reads for ClusterSecretStore. If you cannot upgrade now, the upstream workaround is a policy engine (Kyverno or OPA) that blocks the BeyondTrust provider outright, or validates (Cluster)SecretStore objects so namespace may only be set on a ClusterSecretStore. Rollout is a controller image bump and pod restart in the operator namespace - no node drain, no tenant workload disruption.

References

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