CVE-2025-53798 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 that provides routing and remote access capabilities to Windows servers. The vulnerability arises from improper bounds checking when processing certain network inputs, allowing an attacker to read memory beyond the intended buffer limits. This can lead to unauthorized disclosure of sensitive information residing in adjacent memory areas. The attack vector is network-based (AV:N), requiring no privileges (PR:N), but does require user interaction (UI:R), such as sending crafted packets to the RRAS service. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component without affecting other system components. The impact is high on confidentiality (C:H) but does not affect integrity (I:N) or availability (A:N). The exploitability is considered low complexity (AC:L), and no known exploits have been reported in the wild. No official patches have been released at the time of publication, but the vulnerability is publicly disclosed and assigned a CVSS v3.1 score of 6.5, indicating medium severity. The vulnerability could be leveraged by attackers to gather sensitive information that may facilitate further attacks or reconnaissance activities.

For European organizations, this vulnerability poses a significant risk to the confidentiality of sensitive data processed or transmitted via Windows Server 2019 systems running RRAS. Attackers could remotely extract information that may include configuration details, credentials, or other sensitive memory contents, potentially enabling subsequent targeted attacks or lateral movement within networks. Critical infrastructure sectors such as finance, healthcare, government, and telecommunications that rely on Windows Server 2019 with RRAS enabled are particularly at risk. The lack of required privileges lowers the barrier for exploitation, increasing the threat surface. Although no integrity or availability impact is present, the confidentiality breach could lead to regulatory compliance issues under GDPR and damage organizational reputation. The absence of known exploits provides a window for proactive mitigation, but the public disclosure increases the risk of future exploit development. Organizations with exposed RRAS services on the internet or poorly segmented internal networks face heightened exposure.

1. Immediately audit and inventory all Windows Server 2019 instances running RRAS to identify exposed systems. 2. Restrict RRAS exposure by implementing strict firewall rules to limit access only to trusted networks and hosts. 3. Disable RRAS on servers where it is not essential to reduce the attack surface. 4. Monitor network traffic for unusual or malformed packets targeting RRAS ports and services using intrusion detection/prevention systems (IDS/IPS). 5. Employ network segmentation to isolate critical servers and limit lateral movement opportunities. 6. Apply principle of least privilege for all network services and accounts interacting with RRAS. 7. Stay alert for official Microsoft patches or security advisories and apply updates promptly once available. 8. Conduct regular vulnerability scans and penetration tests focusing on RRAS and related network services. 9. Educate IT staff about this vulnerability and the importance of monitoring and rapid response. 10. Consider deploying endpoint detection and response (EDR) solutions capable of detecting anomalous memory access patterns.