CVE-2025-59502 is a vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) found in Microsoft Windows 10 Version 1809, specifically in the Windows Remote Procedure Call (RPC) service. The flaw allows an unauthenticated attacker to send specially crafted RPC requests over the network that cause the targeted system to consume excessive resources, such as CPU, memory, or network bandwidth. This resource exhaustion leads to a denial of service (DoS) condition, rendering the system unresponsive or causing service interruptions. The vulnerability has a CVSS 3.1 base score of 7.5, indicating high severity, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The scope is unchanged (S:U), and the impact affects availability only (A:H), with no confidentiality or integrity impact. The exploitability level is unproven but theoretically straightforward due to the lack of authentication and user interaction requirements. The vulnerability was reserved in mid-September 2025 and published in October 2025, with no patches or known exploits currently available. This vulnerability is critical for environments still running Windows 10 Version 1809, which is an older release and may no longer receive mainstream support, increasing exposure risk. The RPC service is a core Windows component used for inter-process communication and network services, making this vulnerability a potential vector for widespread disruption if exploited.

For European organizations, the primary impact of CVE-2025-59502 is the risk of denial of service attacks that can disrupt critical business operations, especially those relying on legacy Windows 10 Version 1809 systems. Availability degradation can affect enterprise services, internal communications, and customer-facing applications that depend on RPC. Sectors such as finance, healthcare, manufacturing, and government agencies are particularly vulnerable due to their reliance on stable Windows environments and networked services. The lack of required authentication and user interaction means attackers can launch attacks remotely and anonymously, increasing the threat landscape. Additionally, organizations with limited patch management capabilities or those using extended support versions may face prolonged exposure. Disruptions could lead to operational downtime, financial losses, and reputational damage. The vulnerability also poses risks to critical infrastructure systems that utilize Windows 10 1809, potentially impacting public services and utilities across Europe.

1. Immediate mitigation should focus on network-level controls: implement firewall rules to restrict RPC traffic (typically TCP ports 135, 139, 445, and dynamic RPC ports) to trusted hosts only. 2. Disable or limit RPC services on systems where they are not essential to reduce the attack surface. 3. Upgrade affected systems from Windows 10 Version 1809 to a supported and patched version of Windows 10 or Windows 11 to receive security updates and fixes. 4. Employ intrusion detection and prevention systems (IDS/IPS) to monitor and block anomalous RPC traffic patterns indicative of resource exhaustion attacks. 5. Conduct regular audits of network traffic and system resource usage to detect early signs of exploitation attempts. 6. For environments where immediate upgrades are not feasible, consider isolating legacy systems in segmented network zones with strict access controls. 7. Maintain up-to-date incident response plans that include procedures for mitigating DoS attacks targeting RPC services. 8. Engage with Microsoft support channels to obtain any available patches or workarounds as they become available.