Bluetooth® Low Energy Pairing in Bluetooth Core Specification v4.0 through v5.3 may permit an unauthenticated MITM to acquire credentials with two pairing devices via adjacent access when the MITM negotiates Legacy Passkey Pairing with the pairing Initiator and Secure Connections Passkey Pairing with the pairing Responder and brute forces the Passkey entered by the user into the Initiator. The MITM attacker can use the identified Passkey value to complete authentication with the Responder via Bluetooth pairing method confusion.

Unencrypted Bluetooth Low Energy baseband links in Bluetooth Core Specifications 4.0 through 5.2 may permit an adjacent device to inject a crafted packet during the receive window of the listening device before the transmitting device initiates its packet transmission to achieve full MITM status without terminating the link. When applied against devices establishing or using encrypted links, crafted packets may be used to terminate an existing link, but will not compromise the confidentiality or integrity of the link.

An information leakage vulnerability in the Bluetooth Low Energy advertisement scan response in Bluetooth Core Specifications 4.0 through 5.2, and extended scan response in Bluetooth Core Specifications 5.0 through 5.2, may be used to identify devices using Resolvable Private Addressing (RPA) by their response or non-response to specific scan requests from remote addresses. RPAs that have been associated with a specific remote device may also be used to identify a peer in the same manner by using its reaction to an active scan request. This has also been called an allowlist-based side channel.