There are 2 open security issues in buster.
1 issue left for the package maintainer to handle:
In BlueZ before 5.55, a double free was found in the gatttool disconnect_cb() routine from shared/att.c. A remote attacker could potentially cause a denial of service or code execution, during service discovery, due to a redundant disconnect MGMT event.
You can find information about how to handle this issue in the security team's documentation.
1 ignored issue:
A bug in Bluez may allow for the Bluetooth Discoverable state being set to on when no Bluetooth agent is registered with the system. This situation could lead to the unauthorized pairing of certain Bluetooth devices without any form of authentication. Versions before bluez 5.51 are vulnerable.