CVE-2024-7139 is a medium-severity vulnerability identified in the Silicon Labs RS9116 Bluetooth SDK, specifically involving an out-of-bounds write condition (CWE-787) triggered by an unchecked buffer length in the processing of L2CAP packets. The vulnerability arises when a specially crafted L2CAP packet is received by the Bluetooth stack, causing a buffer overflow that leads to an assertion failure. This assertion failure results in a temporary denial of service (DoS) condition on the affected device. The impact is primarily on availability, as the device's Bluetooth functionality is disrupted. If the device does not have a watchdog timer enabled to automatically recover from the fault, manual intervention via a hard reset is required to restore normal operation. The vulnerability does not affect confidentiality or integrity directly and does not require authentication or user interaction to be exploited, but the attack vector is remote and requires Bluetooth connectivity (AV:A - adjacent network). The CVSS 3.1 base score is 6.5, reflecting a medium severity level due to the ease of exploitation (low complexity, no privileges required) but limited impact scope (availability only). No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects version 0 of the RS9116 Bluetooth SDK, which is used in embedded systems and IoT devices that incorporate Silicon Labs' Bluetooth modules. The root cause is a lack of proper bounds checking on buffer sizes when handling L2CAP packets, a fundamental protocol layer in Bluetooth communication, which could be exploited by an attacker in proximity to the device to disrupt its Bluetooth service temporarily.

For European organizations, the primary impact of CVE-2024-7139 is a temporary denial of service on devices using the RS9116 Bluetooth SDK. This can affect operational continuity in environments relying on Bluetooth connectivity for critical functions, such as industrial automation, healthcare devices, smart building controls, and IoT deployments. The requirement for a hard reset if watchdog timers are not enabled increases downtime and operational disruption. While the vulnerability does not lead to data breaches or persistent compromise, the loss of Bluetooth functionality can degrade service availability and user experience. In sectors like manufacturing or healthcare, where Bluetooth-enabled devices may monitor or control essential processes, this could translate into safety risks or financial losses. The lack of known exploits reduces immediate risk, but the ease of exploitation and the potential for targeted disruption in sensitive environments warrant proactive mitigation. Organizations with extensive IoT or embedded device deployments should assess their exposure and readiness to respond to such DoS conditions.

To mitigate CVE-2024-7139, European organizations should: 1) Verify if their devices use the affected RS9116 Bluetooth SDK version and plan for firmware updates as soon as patches become available from Silicon Labs. 2) Enable and configure watchdog timers on all embedded devices using this SDK to ensure automatic recovery from assertion failures without requiring manual resets. 3) Implement network segmentation and Bluetooth access controls to limit exposure to untrusted or unknown Bluetooth devices, reducing the attack surface. 4) Monitor Bluetooth traffic for anomalous L2CAP packets that could indicate exploitation attempts. 5) Engage with device vendors to confirm patch availability and deployment timelines. 6) Incorporate this vulnerability into incident response plans, ensuring rapid detection and recovery procedures are in place. 7) For critical environments, consider temporary disabling of Bluetooth interfaces if feasible until patches are applied. These steps go beyond generic advice by focusing on specific SDK usage, watchdog timer configuration, and operational controls tailored to embedded Bluetooth devices.