A flaw was found in the containerized-data-importer. The host-assisted cloning feature don't limit which namespaces can be involved in a clone operation, permitting users to clone any PVC in the cluster into their own namespace. This effectively allows user read access to all storage currently allocated to PVCs regardless of namespace.
Acknowledgments: Name: Michael Henriksen (Red Hat), Alexander Wels (Red Hat), Adam Litke (Red Hat)