In the COVIDSafe application through 1.0.21 for Android, unsafe use of the Bluetooth transport option in the GATT connection allows attackers to trick the application into establishing a connection over Bluetooth BR/EDR transport, which reveals the public Bluetooth address of the victim's phone without authorisation, bypassing the Bluetooth address randomisation protection in the user's phone.
OpenTrace, as used in COVIDSafe through v1.0.17, TraceTogether, ABTraceTogether, and other applications on iOS and Android, allows remote attackers to conduct long-term re-identification attacks and possibly have unspecified other impact, because of how Bluetooth is used.