CVE-2025-54093 is a time-of-check to time-of-use (TOCTOU) race condition vulnerability classified under CWE-367, found in the TCP/IP stack of Microsoft Windows 10 Version 1809 (build 17763.0). This vulnerability arises when the system performs a security check on a resource and then uses that resource without revalidating it, allowing an attacker to exploit the timing gap to manipulate the resource state. Specifically, an authorized local attacker with low privileges can race the system's TCP/IP processing to escalate their privileges to higher levels, potentially SYSTEM or administrator. The vulnerability does not require user interaction but does require local access, making it a local privilege escalation (LPE) vector. The CVSS v3.1 base score is 7.0, indicating high severity, with metrics AV:L (local attack vector), AC:H (high complexity), PR:L (low privileges), UI:N (no user interaction), and impacts on confidentiality, integrity, and availability all rated high. No public exploits or patches are currently available, but the vulnerability is publicly disclosed and should be considered a significant risk for affected systems. The root cause is a race condition in the TCP/IP stack, which is critical for network communication, meaning exploitation could have broad system impact. This vulnerability is particularly concerning for environments where Windows 10 1809 remains in use, especially in enterprise or industrial control systems that rely on legacy software.

For European organizations, the impact of CVE-2025-54093 can be severe. Successful exploitation allows an attacker with low-level local access to escalate privileges, potentially gaining full control over affected systems. This can lead to unauthorized access to sensitive data, disruption of critical services, and the ability to deploy further malware or ransomware. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the potential for system compromise and data breaches. The vulnerability affects Windows 10 Version 1809, which is still in use in many enterprises due to legacy application dependencies or delayed upgrade cycles. The exploitation of this vulnerability could also facilitate lateral movement within networks, increasing the scope of compromise. Given the high impact on confidentiality, integrity, and availability, European organizations must prioritize mitigation to prevent potential damage and regulatory consequences under GDPR and other data protection laws.

1. Apply security patches from Microsoft as soon as they become available for Windows 10 Version 1809. Monitor official Microsoft security advisories closely. 2. Restrict local access to systems running Windows 10 1809 by enforcing strict access controls, limiting user privileges, and using endpoint protection solutions to detect suspicious local activity. 3. Employ application whitelisting and behavior monitoring to detect attempts to exploit race conditions or privilege escalation. 4. Where possible, upgrade affected systems to a supported and more recent Windows version that does not contain this vulnerability. 5. Implement network segmentation to limit the ability of an attacker to move laterally after local compromise. 6. Conduct regular security audits and vulnerability assessments focusing on legacy systems to identify and remediate similar risks. 7. Educate IT staff about the risks of TOCTOU vulnerabilities and the importance of timely patching and system hardening.