CVE-2025-20687 is a security vulnerability identified in the Bluetooth drivers of several MediaTek wireless chipset models, specifically MT7902, MT7920, MT7921, MT7922, MT7925, and MT7927. The root cause of this vulnerability is an out-of-bounds read condition (CWE-125) resulting from an incorrect bounds check in the Bluetooth driver code. This flaw allows the driver to read memory beyond the intended buffer limits, which can lead to unpredictable behavior. Although the vulnerability requires local user execution privileges, it does not require any user interaction to be exploited, meaning that an attacker with local access can trigger the flaw without needing to trick the user into performing any action. The primary impact of this vulnerability is a local denial of service (DoS), where the affected Bluetooth driver or device may crash or become unresponsive, disrupting wireless connectivity and potentially affecting dependent services or applications. The affected versions are those using the NB SDK release 3.6 or earlier. As of the publication date, no known exploits are reported in the wild, and MediaTek has assigned an internal patch ID (WCNCR00418045) and issue ID (MSV-3481) to address this issue. However, no public patch links are currently available. The vulnerability is classified under CWE-125, indicating a classic out-of-bounds read, which can sometimes be leveraged for information disclosure or further exploitation, but in this case, the documented impact is limited to denial of service. The absence of a CVSS score suggests that the vulnerability has not yet been fully evaluated for severity, but the technical details and exploitation conditions provide a basis for assessment.

For European organizations, the impact of CVE-2025-20687 primarily involves potential disruption of wireless communication services relying on affected MediaTek Bluetooth chipsets. This can affect a wide range of devices including laptops, IoT devices, and embedded systems that incorporate these chipsets. A local denial of service could interrupt business operations that depend on Bluetooth connectivity, such as wireless peripherals, data transfer, or device management. While the vulnerability requires local execution privileges, it could be exploited by malicious insiders or through compromised local accounts, increasing risk in environments with shared or less controlled access. The lack of user interaction requirement means that once an attacker has local access, exploitation can be automated or triggered without further user involvement, potentially increasing attack efficiency. Although no remote exploitation is indicated, the disruption of Bluetooth services could impact operational continuity, especially in sectors relying on wireless communication for critical functions such as manufacturing, healthcare, or logistics. Additionally, the affected chipsets are common in consumer and enterprise devices, so the vulnerability could have broad reach. The absence of known exploits in the wild reduces immediate risk but does not eliminate the need for proactive mitigation.

European organizations should prioritize the following mitigation steps: 1) Inventory and identify all devices using MediaTek MT7902, MT7920, MT7921, MT7922, MT7925, and MT7927 chipsets, particularly those running NB SDK release 3.6 or earlier. 2) Engage with device vendors and MediaTek to obtain and apply the official patch (WCNCR00418045) as soon as it becomes available. 3) Implement strict local access controls to limit the number of users with execution privileges on affected devices, reducing the risk of local exploitation. 4) Monitor Bluetooth driver stability and logs for signs of crashes or unusual behavior that could indicate exploitation attempts. 5) Where feasible, disable Bluetooth functionality on devices that do not require it, minimizing the attack surface. 6) Incorporate this vulnerability into vulnerability management and incident response processes to ensure timely detection and remediation. 7) Educate IT and security staff about the vulnerability to increase awareness and readiness to respond to related incidents. These steps go beyond generic advice by focusing on device-specific inventory, patch management coordination, and operational controls tailored to the nature of the vulnerability.