CVE-2025-29839 is an out-of-bounds read vulnerability classified under CWE-125, discovered in the Windows File Server component of Microsoft Windows 10 Version 1507 (build 10240.0). This vulnerability allows an unauthorized attacker with local access to the affected system to read memory beyond the allocated buffer boundaries. Such out-of-bounds reads can lead to disclosure of sensitive information residing in adjacent memory areas, potentially exposing data that should remain confidential. The vulnerability does not require any privileges (PR:N) or user interaction (UI:N) to be exploited, but the attacker must have local access to the system (AV:L). The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component without affecting other system components. The CVSS v3.1 base score is 4.0, indicating a medium severity primarily due to the limited attack vector and impact confined to confidentiality. There are no known exploits in the wild, and no patches have been released at the time of publication. The vulnerability affects only the initial release of Windows 10, which is considered legacy and out of mainstream support. The technical details suggest that the vulnerability was reserved in March 2025 and published in May 2025. The lack of patch links indicates that mitigation relies on upgrading or applying future updates. This vulnerability highlights risks associated with legacy systems that remain in use in some environments.

For European organizations, the primary impact of CVE-2025-29839 is the potential unauthorized disclosure of sensitive information due to out-of-bounds memory reads on legacy Windows 10 Version 1507 systems. While the vulnerability does not affect system integrity or availability, the confidentiality breach could expose sensitive data, including credentials, configuration details, or other critical information stored in memory. Organizations in sectors such as government, finance, healthcare, and critical infrastructure that may still operate legacy Windows 10 systems are at higher risk. The local access requirement limits remote exploitation, but insider threats or compromised local accounts could leverage this vulnerability. The medium severity score reflects the limited scope and attack vector, but the risk increases if attackers gain local access through other means. European entities with strict data protection regulations (e.g., GDPR) must consider the potential compliance implications of data leakage. Overall, the impact is moderate but should not be overlooked in environments where legacy Windows 10 systems remain operational.

1. Upgrade affected systems from Windows 10 Version 1507 to a supported and fully patched Windows version, such as Windows 10 LTSC or Windows 11, to eliminate the vulnerability. 2. Restrict local access to systems running legacy Windows 10 builds by enforcing strict access control policies and limiting physical and remote login capabilities to trusted personnel only. 3. Implement endpoint detection and response (EDR) solutions to monitor for suspicious local activity that could indicate exploitation attempts. 4. Enforce the principle of least privilege to minimize the number of users with local access rights. 5. Regularly audit and inventory legacy systems to identify and prioritize remediation of vulnerable devices. 6. Apply network segmentation to isolate legacy systems from critical network segments, reducing the risk of lateral movement. 7. Monitor for any future patches or advisories from Microsoft and apply them promptly once available. 8. Educate IT staff about the risks of running unsupported operating system versions and the importance of timely upgrades.