CVE-2025-53796 is a buffer over-read vulnerability classified under CWE-126 affecting Microsoft Windows Server 2019, specifically version 10.0.17763.0. The flaw exists in the Windows Routing and Remote Access Service (RRAS), a component responsible for routing network traffic and providing VPN and dial-up services. The vulnerability arises from improper bounds checking during processing of network inputs, allowing an attacker to read memory beyond the intended buffer limits. This can lead to disclosure of sensitive information residing in adjacent memory areas, potentially exposing credentials, configuration data, or other confidential information. The attack vector is network-based, requiring no authentication privileges, but does require user interaction in the form of sending crafted packets to the vulnerable service. The CVSS v3.1 score is 6.5 (medium), reflecting high confidentiality impact but no impact on integrity or availability. No known public exploits or patches are currently available, indicating the vulnerability is newly disclosed. The vulnerability's exploitation scope is limited to systems running the specified Windows Server 2019 build with RRAS enabled and exposed to attacker-controlled networks. Given RRAS’s role in network connectivity, successful exploitation could compromise sensitive network information, aiding further attacks or reconnaissance.

For European organizations, this vulnerability poses a risk of sensitive information leakage from critical Windows Server 2019 systems running RRAS. Confidentiality breaches could expose network configurations, authentication tokens, or other sensitive data, potentially facilitating lateral movement or targeted attacks. Organizations in sectors such as finance, government, telecommunications, and critical infrastructure that rely on RRAS for VPN or routing services are particularly vulnerable. The medium severity rating suggests a moderate but non-trivial risk, especially in environments where RRAS is exposed to untrusted networks or the internet. While no denial of service or code execution is possible, the information disclosure could undermine trust in network security and lead to compliance issues under GDPR if personal or sensitive data is exposed. The lack of available patches means organizations must rely on network-level mitigations until updates are released.

1. Immediately audit and inventory all Windows Server 2019 systems to identify those running RRAS, especially version 10.0.17763.0. 2. Restrict RRAS exposure by implementing strict firewall rules to limit access only to trusted networks and known IP addresses. 3. Disable RRAS on servers where it is not essential to reduce the attack surface. 4. Employ network segmentation to isolate RRAS servers from less trusted network zones. 5. Monitor network traffic for unusual or malformed packets targeting RRAS ports to detect potential exploitation attempts. 6. Prepare to deploy Microsoft patches or security updates as soon as they become available; subscribe to official Microsoft security advisories. 7. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures tuned for RRAS anomalies. 8. Educate network administrators about the vulnerability and the importance of limiting RRAS exposure. 9. Review and tighten logging and alerting on RRAS servers to quickly identify suspicious activity. 10. Evaluate alternative VPN or routing solutions if RRAS cannot be sufficiently secured in the interim.