ECK operator: credentials survive an RBAC-denied cross-namespace association, keeping tenant read access

Impact

When a cross-namespace association between a resource and an Elasticsearch cluster is denied by the operator's RBAC enforcement, the credentials created for that association are not cleaned up. A tenant in another namespace therefore keeps read access to an Elasticsearch cluster it was explicitly refused, and the denial looks successful from the operator's side. The CVSS vector is scope-changed, which is the point: on a shared GPU cluster where namespaces are the tenant boundary and Elasticsearch commonly holds job logs, scheduler events and node telemetry from the whole fleet, a leftover credential is one tenant reading another tenant's operational data. The privilege gained is read-only and the attack complexity is rated high, so this is a boundary erosion to close on the next operator upgrade rather than an emergency.

Who can reach it

A low-privileged tenant who can create resources in their own namespace and request an association with an Elasticsearch cluster in another namespace. Authenticated Kubernetes access to at least one namespace is required; no cluster-admin rights are needed.

What to do

Upgrade the ECK operator to 3.5.0, the release named in the Elastic security update ESA-2026-146. That is a controller redeploy - the operator pod restarts while managed Elasticsearch and Kibana workloads keep running, so no GPU node drain and no fleet downtime. Upgrading does not by itself revoke credentials already issued: audit existing association secrets for namespace pairs that RBAC should have denied and delete them, then rotate the affected Elasticsearch user credentials.

References

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