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.

Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device, able to conduct a successful brute-force attack on an insufficiently random AuthValue before the provisioning procedure times out, to complete authentication by leveraging Malleable Commitment.

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.

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