Subscriber-to-Administrator escalation via trusted client cookie

Privilege escalation in Login as User 1.0.1 and earlier allows remote authenticated users to obtain administrator sessions. The handle_return_to_admin() function trusts the client-controlled oclaup_original_admin cookie as the user ID passed to WordPress authentication without verifying an admin-initiated switch. Subscriber-level access is sufficient; triggering Return to Admin replaces the attacker's session with the chosen administrator session.