CVE-2025-59502 is a vulnerability categorized under CWE-400 (Uncontrolled Resource Consumption) found in the Windows Remote Procedure Call (RPC) service of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw allows an unauthenticated attacker to send specially crafted network requests to the RPC service, causing it to consume excessive system resources such as CPU, memory, or network bandwidth. This resource exhaustion can lead to a denial of service (DoS) condition, rendering the affected system unresponsive or causing service interruptions. The vulnerability has a CVSS v3.1 base score of 7.5, indicating high severity. The attack vector is network-based (AV:N), requires no privileges (PR:N) or user interaction (UI:N), and impacts availability (A:H) without affecting confidentiality or integrity. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component or system. No patches or exploits are currently publicly available, but the vulnerability is officially published and reserved since September 2025. The lack of authentication requirements and ease of exploitation make this a significant threat, especially for environments still running Windows 10 Version 1809, which is an older but still in-use OS version in many enterprises.

For European organizations, the primary impact of CVE-2025-59502 is the potential for denial of service attacks that can disrupt critical business operations, especially those relying on Windows 10 Version 1809 systems. This could affect availability of services, internal applications, and networked resources dependent on RPC. Industries such as finance, healthcare, manufacturing, and government agencies that use legacy Windows 10 systems are particularly vulnerable. Disruptions could lead to operational downtime, loss of productivity, and potential financial losses. Additionally, critical infrastructure relying on Windows 10 endpoints or servers could face service outages, impacting public services and safety. Since the vulnerability requires no authentication or user interaction, attackers could launch widespread network-based attacks, increasing the risk of large-scale disruptions in enterprise and public sector networks across Europe.

1. Immediate mitigation should include network-level controls such as firewall rules to restrict inbound RPC traffic to trusted sources only, minimizing exposure to untrusted networks. 2. Employ network intrusion detection and prevention systems (IDS/IPS) to monitor and block suspicious RPC traffic patterns indicative of resource exhaustion attempts. 3. Where possible, isolate or segment legacy Windows 10 Version 1809 systems from critical network segments to limit attack surface. 4. Prioritize upgrading affected systems to a supported and patched Windows version as Microsoft releases security updates addressing this vulnerability. 5. Implement rate limiting on RPC endpoints to prevent excessive request flooding. 6. Conduct regular monitoring of system resource utilization to detect abnormal spikes that may indicate exploitation attempts. 7. Maintain up-to-date asset inventories to identify all systems running the vulnerable OS version for targeted remediation. 8. Educate IT staff on recognizing and responding to potential DoS incidents related to RPC resource exhaustion.