CVE-2025-27742 is an out-of-bounds read vulnerability classified under CWE-125 affecting Microsoft Windows 10 Version 1507 (build 10.0.10240.0). The flaw exists in the NTFS file system driver, where improper bounds checking allows an attacker with local access to read memory beyond intended buffers. This can lead to unauthorized disclosure of sensitive information stored in memory, potentially exposing confidential data to local attackers without requiring elevated privileges. The vulnerability requires user interaction, such as opening a specially crafted file or triggering a specific NTFS operation, but no prior authentication or administrative rights are necessary. The CVSS 3.1 base score is 5.5 (medium severity), with attack vector Local (L), low attack complexity (L), no privileges required (N), user interaction required (R), scope unchanged (U), and high impact on confidentiality (H) but no impact on integrity or availability. No public exploits have been reported yet, and no patches are currently linked, indicating that mitigation primarily involves upgrading from the affected legacy Windows 10 version or applying future security updates from Microsoft. The vulnerability could be leveraged in scenarios where an attacker has local user access, such as through compromised user accounts or physical access, to extract sensitive information from memory buffers related to NTFS operations.

For European organizations, the primary impact of CVE-2025-27742 is the potential unauthorized disclosure of sensitive information residing in memory due to the out-of-bounds read in the NTFS driver. This could include confidential data or security-critical information that attackers might use to further compromise systems or exfiltrate data. Although the vulnerability does not allow privilege escalation or denial of service, the confidentiality breach could undermine trust and compliance with data protection regulations such as GDPR. Organizations relying on legacy Windows 10 Version 1507 systems, especially in sectors with high confidentiality requirements like finance, healthcare, and government, face increased risk if local access controls are weak. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk from insider threats or attackers who gain physical or remote desktop access. The absence of known exploits reduces immediate threat but does not preclude future weaponization. Overall, the impact is moderate but significant for environments with sensitive data and legacy system dependencies.

To mitigate CVE-2025-27742, European organizations should prioritize upgrading affected systems from Windows 10 Version 1507 to supported and patched Windows versions that address this vulnerability. Where immediate upgrades are not feasible, organizations should enforce strict local access controls, including limiting user permissions, implementing robust authentication mechanisms, and monitoring for suspicious local activity. Employing endpoint detection and response (EDR) solutions can help identify attempts to exploit local vulnerabilities. Additionally, organizations should educate users about the risks of opening untrusted files or performing risky NTFS operations that could trigger the vulnerability. Network segmentation and physical security controls can reduce the risk of unauthorized local access. Regularly reviewing and applying Microsoft security advisories and patches as they become available is critical. Finally, conducting vulnerability assessments and penetration testing focused on legacy systems can help identify exposure and validate mitigation effectiveness.