CVE-2021-33155 is a vulnerability identified in the firmware of certain Intel Wireless Bluetooth and Killer Bluetooth products prior to version 22.100. The root cause of this vulnerability is improper input validation (CWE-20) within the firmware, which can be exploited by an authenticated user who has adjacent access to the Bluetooth device. Adjacent access implies that the attacker must be within wireless range to interact with the Bluetooth interface. The vulnerability allows the attacker to trigger a denial of service (DoS) condition, impacting the availability of the Bluetooth functionality on the affected device. The CVSS v3.1 base score is 5.7, indicating a medium severity level. The attack vector is adjacent network (AV:A), requiring low attack complexity (AC:L) and privileges (PR:L), but no user interaction (UI:N). The impact is limited to availability (A:H), with no confidentiality or integrity impact. No known exploits have been reported in the wild as of the published date. This vulnerability affects a broad range of Intel Wireless Bluetooth and Killer Bluetooth products used in laptops, desktops, and other devices, which are common in enterprise and consumer environments. Since the flaw resides in firmware, remediation requires updating the Bluetooth firmware to version 22.100 or later where the input validation issue has been addressed. The vulnerability could be leveraged by an attacker in close proximity to disrupt Bluetooth communications, potentially impacting wireless peripherals, data transfers, and device connectivity reliant on Bluetooth technology.

For European organizations, this vulnerability poses a risk primarily to the availability of Bluetooth services on affected devices. Organizations that rely heavily on Bluetooth peripherals such as wireless keyboards, mice, headsets, or IoT devices could experience operational disruptions if an attacker exploits this flaw to cause a denial of service. Critical environments where Bluetooth is used for secure access control or industrial automation could face interruptions, potentially affecting productivity and security operations. However, the requirement for adjacent access and authenticated user privileges limits the attack surface to insiders or physically proximate attackers, reducing the likelihood of widespread remote exploitation. Nonetheless, in dense office environments or public spaces, attackers could exploit this vulnerability to cause targeted disruptions. The absence of confidentiality or integrity impact means sensitive data leakage or manipulation is not a concern here, but availability disruptions could still have significant operational consequences. Organizations with a large deployment of Intel Wireless or Killer Bluetooth devices should prioritize firmware updates to mitigate this risk.

To mitigate this vulnerability effectively, European organizations should: 1) Inventory all devices using Intel Wireless Bluetooth and Killer Bluetooth products to identify those running firmware versions prior to 22.100. 2) Coordinate with device manufacturers and IT asset management teams to obtain and deploy firmware updates that address this vulnerability. 3) Implement physical security controls to limit unauthorized physical proximity to sensitive devices, reducing the risk of adjacent attackers. 4) Monitor Bluetooth device logs and network activity for unusual disconnections or service interruptions that may indicate attempted exploitation. 5) Educate users about the importance of applying firmware updates and maintaining device security hygiene. 6) Where feasible, disable Bluetooth on devices that do not require it to reduce the attack surface. 7) For critical environments, consider segmenting Bluetooth device usage and applying additional access controls to restrict authenticated user privileges that could be leveraged for exploitation.