CVE-2025-29831 is a high-severity use-after-free vulnerability (CWE-416) found in the Remote Desktop Gateway Service component of Microsoft Windows Server 2019 (version 10.0.17763.0). This vulnerability allows an unauthorized attacker to execute arbitrary code remotely over a network without requiring prior authentication, though user interaction is necessary. The flaw arises from improper handling of memory in the Remote Desktop Gateway Service, where a reference to a memory location is used after it has been freed, leading to potential memory corruption. Exploiting this vulnerability could enable attackers to execute arbitrary code with high privileges, compromising confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 7.5, reflecting high severity, with attack vector network (AV:N), attack complexity high (AC:H), no privileges required (PR:N), user interaction required (UI:R), and impacts rated high on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was reserved in March 2025 and published in May 2025, indicating recent discovery and disclosure. Given the critical role of Remote Desktop Gateway in enabling secure remote access to internal networks, exploitation could allow attackers to bypass network defenses and gain control over Windows Server 2019 systems remotely.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Windows Server 2019 in enterprise environments, especially for remote access infrastructure. Successful exploitation could lead to full system compromise, data breaches, disruption of critical services, and lateral movement within corporate networks. This is particularly concerning for sectors with high reliance on remote work and secure remote access, such as finance, healthcare, government, and critical infrastructure. The high impact on confidentiality, integrity, and availability means sensitive data could be exfiltrated or altered, and services could be disrupted, causing operational and reputational damage. The requirement for user interaction slightly reduces the risk but does not eliminate it, as phishing or social engineering could facilitate exploitation. The lack of known exploits currently provides a window for proactive mitigation before active attacks emerge.

European organizations should prioritize the following specific mitigations: 1) Monitor Microsoft security advisories closely for the release of official patches addressing CVE-2025-29831 and apply them promptly once available. 2) Restrict and monitor Remote Desktop Gateway access using network segmentation, VPNs, and strict firewall rules to limit exposure to untrusted networks. 3) Implement multi-factor authentication (MFA) for all remote access services to reduce the risk of successful exploitation via user interaction. 4) Educate users on phishing and social engineering risks to minimize the chance of triggering the vulnerability. 5) Employ endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts. 6) Regularly audit and harden Remote Desktop Gateway configurations, disabling unnecessary features and enforcing least privilege principles. 7) Consider temporary disabling or limiting Remote Desktop Gateway services where feasible until patches are applied. These targeted actions go beyond generic advice by focusing on reducing attack surface and user interaction vectors specific to this vulnerability.