An HTTP parameter pollution issue was discovered on Shenzhen Dragon Brothers Fingerprint Bluetooth Round Padlock FB50 2.3. With the user ID, user name, and the lock’s MAC address, anyone can unbind the existing owner of the lock, and bind themselves instead. This leads to complete takeover of the lock. The user ID, name, and MAC address are trivially obtained from APIs found within the Android or iOS application. With only the MAC address of the lock, any attacker can transfer ownership of the lock from the current user, over to the attacker’s account. Thus rendering the lock completely inaccessible to the current user.