A vulnerability was found in Linux Kernel, where Bluetooth BR/EDR PIN Pairing procedure is vulnerable to an impersonation attack. When an attacker connects to a victim device using the address of the device and the victim initiates a Pairing, the attacker can reflect the encrypted nonce even without knowledge of the key.

Bluetooth BR/EDR devices with Secure Simple Pairing and Secure Connections pairing in Bluetooth Core Specification 4.2 through 5.4 allow certain man-in-the-middle attacks that force a short key length, and might lead to discovery of the encryption key and live injection, aka BLUFFS.

A vulnerability was found in Linux Kernel, where Passkey Entry protocol used in Secure Simple Pairing (SSP), Secure Connections (SC) and LE Secure Connections (LESC) of the Bluetooth Core Specification is vulnerable to an impersonation attack where an active attacker can impersonate the initiating device without any previous knowledge.

Refer: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d19628f539fccf899298ff02ee4c73e4bf6df3f