The edit/delete/pause/run actions of do_manage_tasks gated ownership with
`if owner and task.owner and task.owner != owner`. The middle term made the
check a no-op whenever task.owner was null/empty — the state a scheduled task
sits in when it was created in no-login mode (or via the localhost middleware
bypass) before the periodic legacy-owner sweep reassigns it to the admin user.
Any authenticated user's agent could then edit, delete, pause, or run another
tenant's owner-less task; edit+run lets an attacker rewrite the task prompt and
execute it in the scheduler's agent context.
The sibling `list` action already scopes with an exact `owner == owner` filter,
so the mutators were strictly more permissive than the reader. Drop the middle
term so the guard fails closed on owner-less rows for authenticated callers,
matching `list` and the calendar/notes/gallery/session null-owner gates. Auth
disabled (owner falsy) and same-owner access are unchanged.
Ashvin
a8d215a390