Devices supporting Bluetooth before 5.1 may allow man-in-the-middle attacks, aka BLURtooth. Cross Transport Key Derivation in Bluetooth Core Specification v4.2 and v5.0 may permit an unauthenticated user to establish a bonding with one transport, either LE or BR/EDR, and replace a bonding already established on the opposing transport, BR/EDR or LE, potentially overwriting an authenticated key with an unauthenticated key, or a key with greater entropy with one with less.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15802
Reference (s):
- https://www.bluetooth.com/learn-about-bluetooth/bluetooth-technology/bluetooth-security/blurtooth/
- https://gizmodo.com/bluetooth-unveils-its-latest-security-issue-with-no-se-1845013709
- https://www.kb.cert.org/vuls/id/589825