The Bluetooth BR/EDR specification up to and including version 5.1 permits sufficiently low encryption key length and does not prevent an attacker from influencing the key length negotiation. This allows practical brute-force attacks (aka "KNOB") that can decrypt traffic and inject arbitrary ciphertext without the victim noticing. CREATE(Triage):(User=admin) CVE-2019-9506 (https://nvd.nist.gov/vuln/detail/CVE-2019-9506)
