CVE-2024-30085 is a high-severity heap-based buffer overflow vulnerability (CWE-122) found in the Windows Cloud Files Mini Filter Driver component of Microsoft Windows 11 version 21H2 (build 10.0.0). This vulnerability allows an attacker with limited privileges (low-level privileges) to perform an elevation of privilege attack, potentially gaining higher system privileges without requiring user interaction. The vulnerability arises from improper handling of memory buffers in the mini filter driver responsible for cloud file synchronization and management. Exploiting this flaw could lead to arbitrary code execution in kernel mode, compromising the confidentiality, integrity, and availability of the affected system. The CVSS v3.1 score of 7.8 reflects the significant impact on confidentiality, integrity, and availability, combined with the requirement for local access and low privileges but no user interaction. Although no known exploits are currently reported in the wild, the presence of a heap-based buffer overflow in a kernel component makes this vulnerability a critical target for attackers seeking to escalate privileges on Windows 11 systems. The vulnerability was reserved in March 2024 and published in June 2024, indicating recent discovery and disclosure. No official patches or mitigations have been linked yet, so affected organizations must monitor for updates and apply them promptly once available.

For European organizations, this vulnerability poses a serious risk, especially in environments running Windows 11 version 21H2. Successful exploitation could allow attackers to escalate privileges from a low-level user to SYSTEM or kernel-level access, enabling them to install persistent malware, exfiltrate sensitive data, disrupt operations, or move laterally within networks. This is particularly concerning for sectors with high-value targets such as finance, government, healthcare, and critical infrastructure, where confidentiality and integrity are paramount. The requirement for local access limits remote exploitation but does not eliminate risk, as attackers could leverage social engineering, phishing, or compromised credentials to gain initial footholds. The lack of user interaction requirement further increases risk, as exploitation can occur silently once local access is obtained. Given the widespread adoption of Windows 11 in enterprise environments across Europe, this vulnerability could facilitate sophisticated attacks against corporate and governmental systems, potentially leading to data breaches, operational disruption, and reputational damage.

European organizations should implement the following specific mitigations: 1) Immediately inventory and identify all systems running Windows 11 version 21H2 to assess exposure. 2) Apply any available Microsoft security updates or patches as soon as they are released for this vulnerability. 3) Restrict local access to critical systems by enforcing strict access controls, including the use of multi-factor authentication and least privilege principles to limit the number of users with local login capabilities. 4) Monitor endpoint and kernel-level activity for unusual behavior indicative of exploitation attempts, such as unexpected privilege escalations or anomalous calls to the Cloud Files Mini Filter Driver. 5) Employ application whitelisting and endpoint detection and response (EDR) solutions capable of detecting exploitation techniques related to heap-based buffer overflows and kernel driver manipulation. 6) Educate users on the risks of phishing and social engineering that could lead to initial local access. 7) Consider temporarily disabling or restricting the Cloud Files Mini Filter Driver functionality if feasible and if it does not disrupt critical business processes, until patches are applied.