title: Blutooth BR/EDR specification does not specify sufficient encryption key length and allows an attacker to influence key length negotiation
description: 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.
problem types: CWE-310 Cryptographic Issues
affected:
{
platforms: N/A
product: BR/EDR
vendor: Bluetooth
versions:
lessThanOrEqual: 5.1, status: affected, version: 5.1, versionType: custom
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: LOW
baseScore: 7.6
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: LOW
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
version: 3.0
]
workarounds: Bluetooth SIG Expedited Errata Correction 11838