EEF-CVE-2026-82748

Ash.Actions.Aggregate authorizes an aggregate under one action but computes it under another

## Summary Incorrect Authorization vulnerability in ash-project ash authorizes an aggregate under one read action while computing it under another, so an aggregate can run with policies that do not match the action it was authorized against. `Ash.Actions.Aggregate` groups aggregates by their `{authorize?, read_action}` and authorizes each group under that read action, but when building the data query it selected the action as `opts[:action] || read_action || <primary read>` (`lib/ash/actions/aggregate.ex`). When a caller passed an `:action` option, the aggregate query ran under that action while authorization had been computed for the group's own `read_action`. If the run action's read policies are more permissive than the authorized one, the aggregate (a count or sum) is computed over records the authorized action's policies would have excluded, disclosing information about data the actor cannot read. The fix runs the aggregate under the same `read_action` it is authorized against. This issue affects ash: from 3.5.13 before 3.32.2.