Legacy pairing and secure-connections pairing authentication in Bluetooth BR/EDR Core Specification v5.2 and earlier may allow an unauthenticated user to complete authentication without pairing credentials via adjacent access. An unauthenticated, adjacent attacker could impersonate a Bluetooth BR/EDR master or slave to pair with a previously paired remote device to successfully complete the authentication procedure without knowing the link key.

Pairing in Bluetooth® Core v5.2 and earlier may permit an unauthenticated attacker to acquire credentials with two pairing devices via adjacent access when the unauthenticated user initiates different pairing methods in each peer device and an end-user erroneously completes both pairing procedures with the MITM using the confirmation number of one peer as the passkey of the other. An adjacent, unauthenticated attacker could be able to initiate any Bluetooth operation on either attacked device exposed by the enabled Bluetooth profiles. This exposure may be limited when the user must authorize certain access explicitly, but so long as a user assumes that it is the intended remote device requesting permissions, device-local protections may be weakened.