Magento LTS is the official OpenMage LTS codebase. Guest orders may be viewed without authentication using a "guest-view" cookie which contains the order's "protect_code". This code is 6 hexadecimal characters which is arguably not enough to prevent a brute-force attack. Exposing each order would require a separate brute force attack. This issue has been patched in versions 19.5.1 and 20.1.1.