CVE-2024-37986 is a vulnerability classified under CWE-191 (Integer Underflow) that affects Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability specifically targets the Secure Boot security feature, which is designed to ensure that only trusted software is loaded during the system boot process. An integer underflow or wraparound occurs when an arithmetic operation causes a value to wrap around to an unexpected value, often zero or a very large number, due to exceeding the minimum representable integer value. In this case, the flaw allows an attacker to bypass Secure Boot protections, potentially enabling the loading of unauthorized or malicious boot components. The CVSS 3.1 base score is 8.0 (high), with an attack vector of 'Adjacent' (AV:A), low attack complexity, no privileges required, but user interaction is necessary. The scope is unchanged, and the impact on confidentiality, integrity, and availability is high, indicating that a successful exploit could fully compromise the affected system. Although no known exploits are currently in the wild, the vulnerability represents a serious risk for systems that have not been updated or patched. The lack of available patches at the time of publication suggests that organizations must prioritize mitigation through other means, such as upgrading to newer Windows versions or applying interim security controls. This vulnerability is particularly concerning because Secure Boot is a critical security mechanism designed to prevent rootkits and boot-level malware, and bypassing it undermines the foundational trust model of the system's startup process.

For European organizations, the impact of CVE-2024-37986 can be severe, especially in sectors that rely on legacy Windows 10 Version 1809 deployments, such as government agencies, healthcare, finance, and critical infrastructure. A successful exploitation could allow attackers to bypass Secure Boot, enabling the execution of malicious code early in the boot process, which can evade traditional endpoint security solutions. This could lead to persistent malware infections, data breaches, ransomware attacks, and disruption of critical services. The requirement for user interaction and network adjacency means targeted phishing or social engineering campaigns combined with network access could be used to exploit this vulnerability. Given the high confidentiality, integrity, and availability impacts, organizations could face significant operational and reputational damage, regulatory penalties under GDPR for data breaches, and increased costs for incident response and recovery.

1. Upgrade affected systems from Windows 10 Version 1809 to a supported and fully patched Windows version (e.g., Windows 10 21H2 or later, or Windows 11). 2. Monitor Microsoft security advisories closely for the release of official patches addressing CVE-2024-37986 and apply them promptly. 3. Implement network segmentation and strict access controls to limit exposure to adjacent network attacks, reducing the attack surface. 4. Enforce strong user awareness training to reduce the risk of social engineering and user interaction exploitation vectors. 5. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous boot-time activities or unauthorized firmware modifications. 6. Regularly audit Secure Boot configurations and ensure it is enabled and properly configured on all devices. 7. Maintain comprehensive backups and incident response plans to mitigate potential ransomware or persistent malware infections resulting from exploitation.