CVE-2024-30066 is a heap-based buffer overflow vulnerability classified under CWE-122, affecting the Winlogon component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). Winlogon is a critical system process responsible for handling user logins and authentication. The vulnerability allows an attacker with low privileges (PR:L) and local access (AV:L) to execute a buffer overflow in heap memory, which can lead to elevation of privilege (EoP). The flaw does not require user interaction (UI:N) and has low attack complexity (AC:L), making exploitation feasible if an attacker gains local access. The vulnerability impacts system integrity (I:H) but does not affect confidentiality or availability. The scope is unchanged (S:U), meaning the exploit affects only the vulnerable component without extending to other system components. No known exploits have been reported in the wild, and no official patches have been released at the time of publication. The CVSS v3.1 base score is 5.5, indicating medium severity. The vulnerability was reserved in March 2024 and published in June 2024. Given that Windows 10 Version 1809 is an older release with extended support ended or limited, many organizations may still run this version in legacy environments, increasing exposure risk. The absence of patches necessitates immediate risk mitigation through access controls and monitoring. Once patches are available, prompt application is critical to prevent exploitation. The vulnerability's presence in a core authentication process like Winlogon elevates its potential impact on system security and trustworthiness.

For European organizations, the primary impact of CVE-2024-30066 is the potential for local attackers to escalate privileges on systems running Windows 10 Version 1809. This could allow adversaries to gain administrative control, bypass security controls, and deploy further malicious activities such as installing persistent malware or accessing sensitive data indirectly. Critical sectors such as government, finance, healthcare, and industrial control systems that may still operate legacy Windows 10 environments are particularly at risk. The vulnerability does not directly compromise confidentiality or availability but undermines system integrity, which can lead to broader security breaches. Since exploitation requires local access, insider threats or attackers who have already compromised lower-privileged accounts pose the greatest danger. The lack of current exploits reduces immediate risk but also means organizations must be proactive in patching and monitoring. Failure to address this vulnerability could lead to significant operational disruptions and data integrity issues, especially in environments where Windows 10 1809 remains in use due to compatibility or upgrade constraints.

1. Restrict local access to systems running Windows 10 Version 1809 by enforcing strict access controls and limiting user privileges to the minimum necessary. 2. Monitor system logs and security events for unusual local activity indicative of privilege escalation attempts, focusing on Winlogon-related processes. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious behavior. 4. Plan and expedite migration from Windows 10 Version 1809 to a supported and patched Windows version to eliminate exposure to this and other legacy vulnerabilities. 5. Once Microsoft releases an official patch, prioritize its deployment across all affected systems, including those in isolated or less frequently updated environments. 6. Conduct regular vulnerability assessments and penetration tests to identify and remediate privilege escalation vectors. 7. Educate IT staff and users about the risks of local privilege escalation and the importance of maintaining updated systems. 8. Use network segmentation to isolate legacy systems and reduce the risk of lateral movement by attackers who gain local access.