DescriptionXiaozhi-esp32-server before 0.9.8 contains an insecure direct object reference vulnerability in the manager-api DeviceController.getAddressBook handler that allows authenticated users to read other users' device address books. Attackers with a normal or self-registered account can request /device/address-book/{macAddress} with another user's device MAC to obtain contact MACs, aliases, call permissions, and owner user IDs.