CVE-2024-30040 is a vulnerability identified in the MSHTML platform component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The root cause is improper input validation (CWE-20), which allows an attacker to bypass security features designed to protect the system. Specifically, this vulnerability can be triggered remotely (AV:N) with low attack complexity (AC:L), no privileges required (PR:N), but requires user interaction (UI:R). The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component or user context. Successful exploitation can lead to high impact on confidentiality, integrity, and availability (C:H/I:H/A:H), potentially allowing an attacker to execute arbitrary code or escalate privileges. The exploitability is functional (E:F), and the vulnerability is officially published and tracked by Microsoft and CISA, though no active exploits have been observed in the wild. The vulnerability affects legacy Windows 10 installations that have not been upgraded or patched, posing a risk especially in environments where Windows 10 Version 1809 remains in use due to compatibility or operational constraints. The lack of available patches at the time of publication necessitates immediate attention to mitigation strategies.

For European organizations, this vulnerability presents a significant risk due to the widespread use of Windows 10 in enterprise environments, including critical infrastructure, government, healthcare, and finance sectors. Exploitation could lead to unauthorized access, data breaches, ransomware deployment, or disruption of services. The high impact on confidentiality, integrity, and availability means sensitive data could be exfiltrated or altered, and systems could be rendered inoperable. Organizations relying on legacy Windows 10 Version 1809 installations are particularly vulnerable, as these systems may lack modern security controls and timely patching. The requirement for user interaction suggests phishing or social engineering could be vectors, increasing the risk in sectors with large user bases. The absence of known exploits in the wild provides a window for proactive defense, but also implies attackers may develop exploits soon, especially given the high CVSS score.

1. Upgrade affected systems from Windows 10 Version 1809 to the latest supported Windows versions (e.g., Windows 10 22H2 or Windows 11) to eliminate the vulnerable MSHTML component. 2. If upgrading is not immediately possible, monitor Microsoft security advisories closely for patches or workarounds and apply them promptly. 3. Implement strict email filtering and user awareness training to reduce the risk of phishing attacks that could trigger the vulnerability. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block exploitation attempts. 5. Restrict or disable legacy MSHTML usage where feasible, especially in browsers or applications that render HTML content. 6. Conduct vulnerability scanning and asset inventory to identify all systems running Windows 10 Version 1809 and prioritize remediation. 7. Enforce network segmentation to limit lateral movement if a system is compromised. 8. Maintain regular backups and incident response plans to mitigate potential ransomware or destructive attacks leveraging this vulnerability.