CVE-2025-30394 is a medium-severity vulnerability identified in Microsoft Windows Server 2019, specifically affecting version 10.0.17763.0. The vulnerability is categorized under CWE-591, which pertains to sensitive data storage in improperly locked memory. The issue resides within the Remote Desktop Gateway Service, a component that facilitates secure remote connections to internal network resources. Improper locking of memory means that sensitive data handled by this service is not adequately protected against unauthorized access or leakage in memory. Although the vulnerability itself does not directly compromise confidentiality or integrity, it allows an unauthorized attacker to cause a denial of service (DoS) over the network. The CVSS v3.1 score is 5.9 (medium), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), but has high attack complexity (AC:H). The impact is limited to availability (A:H), with no impact on confidentiality or integrity. 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. The Remote Desktop Gateway Service is critical in enterprise environments for secure remote access, and disruption can affect business continuity and remote workforce operations.

For European organizations, the impact of this vulnerability primarily concerns availability disruption of Remote Desktop Gateway Services. Organizations relying heavily on Windows Server 2019 for remote access, especially those with remote or hybrid workforce models, may experience service outages or degraded access capabilities if exploited. This can lead to operational downtime, reduced productivity, and potential cascading effects on dependent services. While no direct data breach or integrity compromise is indicated, denial of service attacks can be leveraged as part of multi-stage attacks or to distract security teams. Critical infrastructure, financial institutions, healthcare providers, and government agencies in Europe that depend on secure remote access could face significant operational risks. The medium severity suggests that while the threat is not immediately critical, it requires timely attention to prevent disruption, especially in sectors where availability is paramount.

Given the absence of an official patch link, European organizations should implement the following specific mitigations: 1) Restrict network exposure of the Remote Desktop Gateway Service by limiting access to trusted IP ranges and enforcing strict firewall rules. 2) Employ network-level authentication and multi-factor authentication to reduce unauthorized access attempts. 3) Monitor Remote Desktop Gateway logs and network traffic for unusual patterns indicative of DoS attempts or memory exploitation. 4) Apply system hardening best practices, including disabling unnecessary services and ensuring Windows Server 2019 is fully updated with the latest cumulative security updates. 5) Consider deploying network-based DoS protection solutions such as intrusion prevention systems (IPS) and rate limiting to mitigate potential attack traffic. 6) Prepare incident response plans specifically addressing availability disruptions of remote access services. 7) Once Microsoft releases an official patch, prioritize its deployment in all affected environments. These targeted actions go beyond generic advice by focusing on access control, monitoring, and network protections tailored to the Remote Desktop Gateway Service context.