CVE-2025-27484 is a high-severity vulnerability affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0), specifically within the Windows Universal Plug and Play (UPnP) Device Host component. The vulnerability is categorized under CWE-591, which involves sensitive data storage in improperly locked memory. This means that sensitive information is stored in memory regions that are not adequately protected against unauthorized access, potentially allowing an attacker to read or manipulate this data. The flaw enables an authorized attacker—someone with some level of access to the network—to elevate their privileges remotely over the network without requiring user interaction. The CVSS 3.1 base score is 7.5, indicating a high severity level. The vector string (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) shows that the attack is network-based (AV:N), requires high attack complexity (AC:H), low privileges (PR:L), no user interaction (UI:N), and impacts confidentiality, integrity, and availability to a high degree (C:H/I:H/A:H). The scope remains unchanged (S:U). The vulnerability arises because the UPnP Device Host does not properly lock memory regions that contain sensitive data, potentially exposing this data to unauthorized processes or attackers on the network. Although no known exploits are currently in the wild, the vulnerability's nature and impact make it a significant risk if weaponized. No patch links are provided yet, indicating that remediation may still be pending or in progress. Organizations running Windows 10 Version 1809 should consider this vulnerability critical to address due to the potential for privilege escalation and full system compromise over the network.

For European organizations, the impact of CVE-2025-27484 can be substantial. Windows 10 Version 1809 remains in use in many enterprise environments, particularly in legacy systems or where upgrade cycles are slow due to compatibility or operational constraints. The ability for an attacker to elevate privileges remotely without user interaction means that attackers could gain administrative control over affected systems, leading to data breaches, ransomware deployment, or lateral movement within corporate networks. Confidentiality, integrity, and availability of critical systems and sensitive data could be severely compromised. This is particularly concerning for sectors with stringent data protection requirements such as finance, healthcare, and government institutions within Europe. Additionally, the network-based attack vector increases the risk of widespread exploitation within corporate LANs or connected VPNs. The lack of known exploits currently provides a window for proactive mitigation, but the high severity score underscores the urgency for European organizations to assess their exposure and implement mitigations promptly.

1. Immediate assessment of all Windows 10 Version 1809 systems within the organization to identify vulnerable hosts, prioritizing critical infrastructure and systems exposed to untrusted networks. 2. Apply any available security updates or patches from Microsoft as soon as they are released. In the absence of official patches, consider temporary mitigations such as disabling or restricting the Windows UPnP Device Host service, especially on systems that do not require UPnP functionality. 3. Implement network segmentation to limit exposure of vulnerable systems, ensuring that only trusted devices and users can access critical network segments. 4. Employ strict access controls and monitoring on network traffic related to UPnP services to detect and block suspicious activity. 5. Use endpoint detection and response (EDR) solutions to monitor for unusual privilege escalation attempts or memory access patterns indicative of exploitation attempts. 6. Plan and execute an upgrade strategy to move affected systems off Windows 10 Version 1809 to supported, patched versions of Windows 10 or Windows 11, reducing long-term risk. 7. Conduct user awareness and incident response training focused on detecting and responding to potential exploitation of privilege escalation vulnerabilities.