CVE-2021-33139 in Wireless Bluetooth
Summary
by MITRE • 02/10/2022
Improper conditions check in firmware for some Intel(R) Wireless Bluetooth(R) and Killer(TM) Bluetooth(R) products before version 22.100 may allow an authenticated user to potentially enable denial of service via adjacent access.
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Analysis
by VulDB Data Team • 08/23/2025
This vulnerability affects Intel wireless bluetooth and killer bluetooth products with firmware versions prior to 22.100, representing a critical security flaw that stems from improper conditions checking within the device firmware. The vulnerability specifically impacts the authentication and access control mechanisms that govern how bluetooth devices handle incoming connection requests and operational commands. The flaw allows an authenticated user with adjacent network access to potentially trigger a denial of service condition that could render the bluetooth functionality completely non-operational. This represents a significant risk to endpoint security since bluetooth devices often serve as primary communication channels for various IoT and mobile devices, creating a potential attack surface that adversaries could exploit to disrupt critical wireless communications.
The technical implementation of this vulnerability resides in the firmware layer of the bluetooth chipsets where insufficient validation occurs during the processing of incoming commands or connection attempts. This condition check failure creates a scenario where legitimate authentication processes can be manipulated to cause the device to enter an unstable state or completely halt its bluetooth operations. The vulnerability is classified under CWE-284 which specifically addresses improper access control, and it aligns with ATT&CK technique T1499.002 which covers network denial of service attacks. The improper conditions check suggests that the firmware lacks proper input validation for command parameters or connection state transitions, allowing maliciously crafted requests to bypass normal operational constraints and trigger unexpected device behavior.
From an operational perspective, this vulnerability poses significant risks to organizations relying on bluetooth connectivity for device management, data transfer, or wireless peripheral operations. The adjacent access requirement means that an attacker must be physically present or network-accessible to the target device, but this limitation does not diminish the severity of the impact. The potential for denial of service attacks can disrupt critical business operations, especially in environments where bluetooth devices are integral to wireless infrastructure or industrial control systems. Security professionals should note that the vulnerability affects multiple product lines including both Intel wireless bluetooth and Killer bluetooth products, indicating a widespread firmware issue that requires coordinated patch management across affected device categories.
Mitigation strategies should prioritize immediate firmware updates to version 22.100 or later, which contain the necessary patches to address the improper conditions checking flaw. Organizations should also implement network segmentation to limit adjacent access to bluetooth-enabled devices and consider disabling bluetooth functionality on devices where it is not required for operations. Network monitoring should be enhanced to detect unusual connection patterns or device behavior that might indicate exploitation attempts. Additionally, security teams should conduct vulnerability assessments to identify all affected devices within their environment and establish incident response procedures for potential denial of service events. The vulnerability highlights the importance of firmware security and the need for robust validation mechanisms in embedded systems, particularly in wireless communication devices where the attack surface can directly impact operational continuity and business availability.