Automation-controller: automation-controller: workflowjobnode.ancestor_artifacts lacks prevent_search, exposing no_log set_stats artifacts via orm-traversal count-oracle

A flaw was found in the Ansible Automation Platform automation-controller. The WorkflowJobNode.ancestor_artifacts database column, which stores the raw merged set_stats artifacts propagated between workflow nodes, is not wrapped in prevent_search() and is therefore accepted for arbitrary field lookups by the REST filter backend, even though it is omitted from the API serializer. Because the column is persisted before Ansible's no_log masking is applied, a user with only read access to a workflow — or, via a regular-expression lookup that bypasses the JSON cross-relation filter guard through the world-readable credential-types endpoint, any authenticated user with no roles — can use the result count as a boolean/count oracle to recover, character by character, secret values that a playbook author explicitly marked no_log, including across organizations.