CVE-2025-47998 is a high-severity heap-based buffer overflow vulnerability identified in the Windows Routing and Remote Access Service (RRAS) component of Microsoft Windows Server 2019 (version 10.0.17763.0). This vulnerability arises due to improper handling of memory buffers in RRAS, which can be exploited by an unauthenticated attacker over the network. The attacker can send specially crafted packets to the RRAS service, triggering the overflow condition. This leads to arbitrary code execution with system-level privileges, potentially allowing the attacker to fully compromise the affected server. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow), indicating that the flaw is related to unsafe memory operations on the heap, which can corrupt memory and lead to control flow hijacking. The CVSS v3.1 base score of 8.8 reflects the critical nature of this vulnerability, with attack vector being network (AV:N), no privileges required (PR:N), but requiring user interaction (UI:R), and impacting confidentiality, integrity, and availability at a high level (C:H/I:H/A:H). Although no known exploits are currently reported in the wild, the ease of exploitation and the critical impact make this a significant threat to organizations running Windows Server 2019 with RRAS enabled. The lack of available patches at the time of publication increases the urgency for mitigation and monitoring.

For European organizations, this vulnerability poses a substantial risk, especially for enterprises and service providers relying on Windows Server 2019 for routing, VPN, or remote access services. Successful exploitation could lead to complete system compromise, data breaches, disruption of network services, and lateral movement within corporate networks. Critical infrastructure operators, financial institutions, healthcare providers, and government agencies in Europe that use RRAS for secure remote connectivity are particularly at risk. The potential for loss of confidentiality, integrity, and availability could result in regulatory non-compliance (e.g., GDPR), financial losses, reputational damage, and operational downtime. Given the network-based attack vector and no requirement for prior authentication, attackers can target exposed RRAS services directly, increasing the threat surface. The user interaction requirement (UI:R) suggests that some form of user action, such as responding to a connection request, may be necessary, which could be mitigated by user awareness but still represents a significant risk in automated or unattended environments.

1. Immediate mitigation should include disabling the Routing and Remote Access Service (RRAS) on Windows Server 2019 systems where it is not essential. 2. For systems requiring RRAS, restrict network exposure by limiting access to RRAS ports using firewall rules, allowing only trusted IP addresses or VPN connections. 3. Implement network segmentation to isolate RRAS servers from general user networks and the internet. 4. Monitor network traffic for unusual or malformed packets targeting RRAS ports, employing intrusion detection/prevention systems (IDS/IPS) with updated signatures. 5. Enforce strict user policies and educate users about the risks of interacting with unsolicited remote access prompts to reduce the risk posed by the user interaction requirement. 6. Regularly check for and apply security updates from Microsoft as soon as patches become available. 7. Employ application whitelisting and endpoint protection solutions to detect and block exploitation attempts or post-exploitation activities. 8. Conduct thorough vulnerability assessments and penetration testing focused on RRAS and related network services to identify and remediate exposure.