Capsule: webhook rule typo lets a tenant user retag a namespace and cross tenant boundaries

Impact

Capsule's Helm chart registered its validating webhook against the resource name namespace/finalize instead of namespaces/finalize, so a PUT to /api/v1/namespaces/{namespace}/finalize never matches the rule and the webhook is simply not invoked. A user holding namespaces/finalize RBAC can therefore change the namespace's tenant label - the exact field Capsule uses to decide which tenant owns a namespace. On a shared GPU cluster where Capsule is the thing keeping teams apart, that means a namespace can be moved under a different tenant, taking its quotas, node pools and policy set with it. matchPolicy: Equivalent does not save you here, since it reconciles API group and version, not a misspelled resource name. Affects 0.13.0 through 0.13.5.

Who can reach it

An authenticated cluster user who already holds namespaces/finalize permission on a namespace; no node access needed, just the Kubernetes API.

What to do

Upgrade Capsule to 0.13.6, which corrects the webhook resource name in charts/capsule/templates/configuration.yaml. This is a chart/controller update - roll the Helm release and let the webhook configuration re-apply; no node drain or reboot. Until then, audit who holds namespaces/finalize and review namespace tenant labels for unexpected changes.

References

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