Windows 10, a widely used operating system, has officially reached its end of support as of October 2025. Despite this, over 40% of devices globally continue to run Windows 10, exposing a large attack surface. End of support means Microsoft will cease providing regular security updates and patches for vulnerabilities discovered after this date, except for those organizations that enroll in the Extended Security Updates (ESU) program, which is a paid service offering critical security patches for a limited time. The absence of ongoing patches leaves systems vulnerable to exploitation of newly discovered vulnerabilities, which attackers can leverage to compromise systems, steal data, or disrupt operations. Although no known exploits are currently reported in the wild, the risk increases over time as vulnerabilities accumulate. The threat is compounded by the fact that Windows 10 is deeply integrated into enterprise environments, including critical infrastructure and government systems. The medium severity rating reflects the balance between the widespread presence of Windows 10 and the mitigations available through ESU enrollment or OS upgrades. Organizations that fail to act may face increased risks of ransomware, data breaches, and operational disruptions. This scenario highlights the critical need for organizations to plan and execute timely migrations to supported Windows versions or secure ESU coverage to maintain security integrity.

For European organizations, the end of Windows 10 support presents significant risks. Many enterprises, public sector entities, and critical infrastructure operators still rely on Windows 10, meaning a substantial portion of IT assets could become vulnerable to exploitation. The lack of security patches increases the likelihood of successful cyberattacks, including ransomware, data exfiltration, and system disruptions, which could lead to financial losses, reputational damage, and regulatory penalties under GDPR. The threat is particularly acute for sectors with high compliance requirements such as finance, healthcare, and government. Additionally, attackers may target these unpatched systems as entry points for broader network compromise. The impact on availability and integrity of services could be severe, especially if legacy systems cannot be upgraded promptly. Organizations that do not enroll in the ESU program or migrate to newer Windows versions risk prolonged exposure. This could also affect supply chains and cross-border operations within Europe, amplifying the threat landscape.

European organizations should immediately assess their Windows 10 deployment footprint and develop a clear migration plan to supported operating systems such as Windows 11 or Windows Server 2022. For systems that cannot be upgraded promptly, enrollment in Microsoft's Extended Security Updates (ESU) program is essential to receive critical security patches. Organizations should implement strict network segmentation and access controls to isolate legacy Windows 10 systems and reduce lateral movement risks. Enhanced endpoint detection and response (EDR) solutions should be deployed to monitor for suspicious activities targeting unpatched vulnerabilities. Regular vulnerability scanning and penetration testing can help identify exploitable weaknesses. Additionally, organizations must ensure robust backup and recovery procedures to mitigate ransomware risks. Employee awareness training on phishing and social engineering attacks remains crucial, as attackers may exploit unpatched systems via these vectors. Finally, organizations should maintain close collaboration with cybersecurity authorities and share threat intelligence to stay informed about emerging risks related to Windows 10 end of support.