CVE-2024-30040 is a high-severity security vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting the MSHTML platform, which is the rendering engine used by Internet Explorer and other Windows components. The vulnerability is classified under CWE-20 (Improper Input Validation) and CWE-203 (Information Exposure). This flaw allows an attacker to bypass security features in the MSHTML platform by exploiting improper input validation mechanisms. The vulnerability has a CVSS v3.1 base score of 8.8, indicating a high level of severity. The attack vector is network-based (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R), such as convincing a user to visit a malicious webpage or open a crafted document. The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). The exploitability is functional (E:F), and the report confidence is confirmed (RC:C). Although no known exploits are currently reported in the wild, the vulnerability’s characteristics suggest that exploitation could lead to full system compromise, data leakage, or denial of service by bypassing security features in the MSHTML engine. Since Windows 10 Version 1809 is an older release, it may not receive regular security updates, increasing the risk for unpatched systems. The vulnerability’s root cause is improper input validation, which can allow maliciously crafted input to circumvent security controls, potentially leading to execution of arbitrary code or exposure of sensitive information.

For European organizations, this vulnerability poses a significant risk, especially for those still operating legacy Windows 10 Version 1809 systems. The MSHTML platform is widely used in enterprise environments for legacy web applications and internal tools. Exploitation could lead to unauthorized access to sensitive corporate data, disruption of critical business operations, and potential lateral movement within networks. Given the high impact on confidentiality, integrity, and availability, successful exploitation could result in data breaches, intellectual property theft, and operational downtime. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the sensitivity of their data and the potential regulatory consequences under GDPR and other European data protection laws. The requirement for user interaction means that phishing or social engineering campaigns could be used to trigger the exploit, increasing the attack surface. The absence of known exploits in the wild currently provides a window for proactive mitigation, but the high severity score demands urgent attention to prevent future attacks.

European organizations should prioritize upgrading or patching affected Windows 10 Version 1809 systems. Since no patch links are currently provided, organizations should monitor Microsoft’s official security advisories closely for updates or out-of-band patches. In the interim, disabling or restricting the use of MSHTML where possible can reduce exposure, such as configuring Group Policy to limit Internet Explorer usage or disabling legacy web components. Employing application whitelisting and endpoint detection and response (EDR) solutions can help detect and block exploitation attempts. User awareness training focused on phishing and social engineering can reduce the likelihood of successful user interaction required for exploitation. Network segmentation and strict access controls can limit lateral movement if exploitation occurs. Additionally, organizations should audit their environment to identify and prioritize systems running Windows 10 Version 1809 and plan for migration to supported Windows versions with ongoing security updates. Implementing robust monitoring for unusual MSHTML activity or suspicious network traffic can provide early detection of exploitation attempts.