CVE-2025-48823 is a medium-severity vulnerability affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability arises from cryptographic issues within the Windows Cryptographic Services component. Specifically, it allows an unauthorized attacker to disclose sensitive information over a network without requiring any authentication or user interaction. The vulnerability is categorized under CWE-326, which relates to the use of weak cryptographic primitives or improper cryptographic implementation. The CVSS v3.1 base score is 5.9, indicating a medium severity level. The attack vector is network-based (AV:N), but the attack complexity is high (AC:H), meaning exploitation requires specific conditions or advanced skills. The vulnerability impacts confidentiality (C:H) but does not affect integrity or availability. The scope remains unchanged (S:U), and no privileges or user interaction are required (PR:N/UI:N). No known exploits are currently reported in the wild, and no patches have been linked or published at the time of this report. The vulnerability could allow attackers to intercept or extract sensitive cryptographic information, potentially undermining the security guarantees of encrypted communications or stored data on affected systems. Since Windows 10 Version 1809 is an older release, many organizations may have already migrated to newer versions, but legacy systems remain at risk. The lack of a patch increases the urgency for mitigation through alternative controls or upgrade paths.

For European organizations, the impact of CVE-2025-48823 could be significant, especially for those still operating legacy Windows 10 Version 1809 systems in critical infrastructure, government, finance, healthcare, or industrial sectors. The information disclosure could lead to leakage of sensitive cryptographic keys or data, enabling further attacks such as man-in-the-middle, decryption of confidential communications, or unauthorized access to protected resources. This could compromise confidentiality of personal data protected under GDPR, resulting in regulatory penalties and reputational damage. The vulnerability's network-based nature means that attackers could exploit it remotely, increasing the risk of widespread exposure within enterprise networks. Although exploitation complexity is high, targeted attackers with sufficient resources could leverage this vulnerability as part of a multi-stage attack chain. The absence of a patch means organizations must rely on compensating controls or system upgrades to mitigate risk. Legacy systems in operational technology environments or isolated networks may be particularly vulnerable due to slower patch cycles and limited monitoring capabilities.

Given the absence of an official patch, European organizations should prioritize the following mitigations: 1) Upgrade affected systems from Windows 10 Version 1809 to a supported, patched Windows version where this vulnerability is resolved. 2) Implement network segmentation and strict firewall rules to limit exposure of vulnerable systems to untrusted networks, reducing the attack surface. 3) Employ strong network monitoring and intrusion detection systems to identify anomalous cryptographic or network activity that could indicate exploitation attempts. 4) Enforce strict cryptographic policies and use application-layer encryption to protect sensitive data independently of the underlying OS cryptographic services. 5) Restrict administrative access and enforce least privilege principles to reduce the potential impact of any information disclosure. 6) Conduct regular vulnerability assessments and penetration testing focusing on cryptographic services and legacy systems. 7) Educate IT staff about the risks associated with legacy Windows versions and the importance of timely upgrades and patch management.