Bluetooth peer impersonation via reflected public key

Authentication bypass in affected Microsoft Windows releases allows physically proximate attackers to impersonate a Bluetooth pairing initiator. The Passkey Entry implementation accepts a remote public key whose X coordinate matches the local key, letting crafted responses reveal the initiator passkey bit by bit and authenticate the attacker to the responder. Exploitation requires wireless range of two vulnerable devices actively pairing with Passkey Entry; it exposes the responder as an encrypted, authenticated peer but does not pair the attacker with the initiator.