CVE-2021-39987 is a high-severity vulnerability identified in Huawei's HarmonyOS version 2.0, specifically within the HwNearbyMain module. The vulnerability is classified as a data processing error (CWE-843), which can lead to a process restart upon successful exploitation. The vulnerability does not require any privileges or user interaction to exploit (CVSS vector: AV:N/AC:L/PR:N/UI:N), making it remotely exploitable over the network without authentication. The impact is limited to availability, as the vulnerability causes a denial-of-service condition by forcing the affected process to restart, potentially disrupting normal system operations. No confidentiality or integrity impacts are reported. The vulnerability's CVSS score is 7.5, indicating a high severity level. Although no known exploits are currently reported in the wild, the ease of exploitation and the lack of required privileges make this a notable threat. The absence of a patch link suggests that remediation may require vendor intervention or updates that must be obtained through official Huawei channels. The vulnerability affects HarmonyOS 2.0, an operating system primarily deployed on Huawei devices, including smartphones, IoT devices, and other smart hardware. The HwNearbyMain module likely handles nearby device communication or data exchange, so exploitation could disrupt these functionalities, impacting device usability and connected services.

For European organizations, the impact of CVE-2021-39987 depends largely on the extent of HarmonyOS device deployment within their infrastructure or user base. Organizations using Huawei devices running HarmonyOS 2.0, especially in sectors relying on IoT or smart devices (e.g., manufacturing, smart buildings, telecommunications), may experience service disruptions due to process restarts triggered by this vulnerability. This could lead to temporary denial of service in critical systems, affecting operational continuity. While the vulnerability does not compromise data confidentiality or integrity, availability interruptions could degrade user experience, delay business processes, or cause cascading failures in interconnected systems. Given Huawei's significant market share in telecommunications and consumer electronics in some European countries, the threat could affect both private enterprises and public sector entities. Additionally, organizations involved in supply chains or services that integrate Huawei HarmonyOS devices should consider the risk of operational disruption. However, the lack of known exploits in the wild reduces immediate risk, though proactive mitigation is advisable to prevent future exploitation.

To mitigate CVE-2021-39987, European organizations should: 1) Inventory all Huawei devices running HarmonyOS 2.0 within their environment to assess exposure. 2) Monitor Huawei's official security advisories for patches or updates addressing this vulnerability and apply them promptly once available. 3) Implement network segmentation and access controls to limit exposure of vulnerable devices to untrusted networks, reducing the attack surface. 4) Employ intrusion detection and prevention systems to monitor for anomalous activity targeting the HwNearbyMain module or related network communications. 5) Where possible, disable or restrict functionalities related to nearby device communication if not required, minimizing the attack vector. 6) Engage with Huawei support channels to obtain guidance on interim mitigations or firmware updates. 7) Conduct regular security assessments and penetration testing focusing on IoT and mobile device security to detect potential exploitation attempts early. These steps go beyond generic advice by focusing on device-specific controls, vendor engagement, and network-level protections tailored to the affected module and product.