CVE-2025-53798 is a buffer over-read 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 is classified under CWE-126, which involves reading data beyond the intended buffer boundaries, potentially exposing sensitive information. The flaw allows an unauthorized attacker to send specially crafted network packets to the RRAS service, causing it to read memory areas outside the allocated buffer. This can lead to the disclosure of sensitive information over the network without requiring any prior authentication, although user interaction is required to trigger the vulnerability. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The attack vector is network-based (AV:N), with low attack complexity (AC:L), no privileges required (PR:N), but requires user interaction (UI:R). The scope is unchanged (S:U), and the impact is high on confidentiality (C:H), with no impact on integrity (I:N) or availability (A:N). No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was reserved in July 2025 and published in September 2025. The RRAS service is commonly used to provide routing and remote access capabilities, including VPN and dial-up services, making it a critical component in enterprise network infrastructure. Exploitation could allow attackers to glean sensitive information from server memory, potentially aiding further attacks or reconnaissance.

For European organizations, this vulnerability poses a significant risk to the confidentiality of sensitive data handled by Windows Server 2019 systems running RRAS. Many enterprises, government agencies, and service providers in Europe rely on Windows Server infrastructure for remote access and routing services. An attacker exploiting this vulnerability could obtain sensitive information such as authentication tokens, configuration data, or other memory-resident secrets, which could facilitate lateral movement or further compromise. Although the vulnerability does not directly affect system integrity or availability, the confidentiality breach could lead to compliance violations under GDPR and other data protection regulations, resulting in legal and financial repercussions. Additionally, organizations with remote access services exposed to untrusted networks are at higher risk. The requirement for user interaction may limit automated exploitation but does not eliminate risk, especially in environments where social engineering or phishing could be used to trigger the vulnerability. The absence of known exploits in the wild currently reduces immediate threat levels but does not preclude future exploitation once proof-of-concept code or weaponized exploits become available.

Given the absence of an official patch at the time of this report, European organizations should implement several targeted mitigations. First, restrict network exposure of RRAS services by limiting access to trusted networks and enforcing strict firewall rules to block unsolicited inbound traffic to RRAS ports. Employ network segmentation to isolate critical servers running Windows Server 2019 with RRAS from less secure network zones. Monitor network traffic for anomalous patterns that could indicate attempts to exploit this vulnerability, focusing on unusual packets targeting RRAS. Implement strict user awareness training to reduce the risk of social engineering that could trigger the required user interaction. Enable enhanced logging and auditing on RRAS servers to detect suspicious activity promptly. Once Microsoft releases a security update, prioritize its deployment in all affected environments. Additionally, consider disabling RRAS services temporarily if they are not essential, or replacing them with alternative secure remote access solutions until a patch is available. Employ endpoint detection and response (EDR) tools to identify potential exploitation attempts and respond swiftly.