CVE-2025-50163 is a heap-based buffer overflow vulnerability identified in the Windows Routing and Remote Access Service (RRAS) component of Microsoft Windows Server 2019, specifically version 10.0.17763.0. This vulnerability arises from improper handling of input data in the RRAS service, which allows an attacker to overflow a heap buffer. Exploitation can be performed remotely over the network without requiring prior authentication, though it requires user interaction. Successful exploitation enables arbitrary code execution with the privileges of the RRAS service, potentially leading to full system compromise. The vulnerability affects confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 8.8, reflecting high severity due to network attack vector, low attack complexity, no privileges required, but user interaction needed. Currently, there are no known exploits in the wild and no official patches released. The vulnerability was reserved in June 2025 and published in August 2025. Given the critical role of RRAS in routing and remote access, exploitation could disrupt network services and allow attackers to establish persistent footholds within enterprise networks.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and service providers relying on Windows Server 2019 with RRAS enabled for remote access or routing functions. Exploitation could lead to unauthorized remote code execution, enabling attackers to steal sensitive data, disrupt network services, or move laterally within networks. Critical infrastructure sectors such as energy, finance, healthcare, and government agencies are particularly vulnerable due to their reliance on secure remote access and network routing. The potential for widespread disruption and data breaches could have severe operational and reputational consequences. The lack of available patches increases the urgency for interim mitigations. Additionally, the requirement for user interaction may limit automated exploitation but does not eliminate risk, especially in environments with frequent remote access or user-initiated network connections.

1. Immediately assess and inventory all Windows Server 2019 systems running RRAS, focusing on version 10.0.17763.0. 2. Disable RRAS on servers where it is not essential to reduce the attack surface. 3. Restrict network exposure of RRAS services using firewalls and network segmentation to limit access to trusted hosts only. 4. Implement strict monitoring and logging of RRAS-related network traffic and system events to detect anomalous activity indicative of exploitation attempts. 5. Educate users about the risk of interacting with unsolicited network prompts or connections that could trigger exploitation. 6. Apply any forthcoming security updates from Microsoft promptly once available. 7. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures targeting RRAS exploitation attempts. 8. Review and enforce least privilege principles for services and accounts associated with RRAS to minimize impact if compromised. 9. Conduct penetration testing and vulnerability scanning focused on RRAS to identify potential exposure. 10. Develop and test incident response plans specific to remote code execution scenarios on critical servers.