CVE-2025-24996 is a vulnerability classified under CWE-73 (External Control of File Name or Path) affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability arises from improper handling of file names or paths in the context of NTLM authentication, allowing an attacker on the network to manipulate these parameters externally. This manipulation can lead to spoofing attacks, where the attacker deceives systems or users by masquerading as a trusted entity. The attack vector is network-based (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R), such as clicking a malicious link or opening a crafted file. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component. The vulnerability primarily impacts confidentiality (C:H) without affecting integrity or availability. No patches or exploits are currently publicly available, but the vulnerability is officially published and recognized by Microsoft and CISA. The flaw is significant because NTLM is still widely used in many enterprise environments for legacy authentication, and external control of file paths can facilitate sophisticated spoofing attacks that may lead to credential theft or unauthorized access. The lack of integrity and availability impact reduces the overall severity, but the confidentiality risk remains substantial, especially in environments where sensitive data is transmitted over NTLM-authenticated sessions.

For European organizations, the primary impact of CVE-2025-24996 is the potential compromise of confidentiality through network spoofing attacks leveraging NTLM authentication weaknesses. Organizations relying on Windows 10 Version 1809, particularly those that have not upgraded to newer Windows versions or disabled NTLM, are at risk. This vulnerability could be exploited to intercept or redirect authentication attempts, potentially leading to unauthorized access to sensitive systems or data. Critical sectors such as finance, government, healthcare, and energy, which often maintain legacy systems or have complex network environments, may face increased risk. The attack requires user interaction, which somewhat limits mass exploitation but does not eliminate targeted spear-phishing or social engineering attacks. The absence of known exploits in the wild currently reduces immediate risk but does not preclude future exploitation. The medium severity rating suggests that while the vulnerability is serious, it is not critical, but it should be addressed promptly to prevent escalation or chaining with other vulnerabilities.

To mitigate CVE-2025-24996, European organizations should: 1) Disable NTLM authentication where feasible, replacing it with more secure protocols such as Kerberos or modern authentication frameworks; 2) Apply strict network segmentation and access controls to limit exposure of NTLM-enabled systems; 3) Educate users to recognize and avoid phishing attempts that could trigger the required user interaction for exploitation; 4) Monitor network traffic for anomalous NTLM authentication requests or suspicious file path manipulations; 5) Upgrade affected systems from Windows 10 Version 1809 to supported, patched versions of Windows that do not contain this vulnerability; 6) Implement application whitelisting and endpoint protection to detect and block attempts to exploit path manipulation; 7) Regularly audit and harden group policies related to authentication and file path handling; 8) Stay informed about vendor updates and apply patches promptly once available; 9) Employ multi-factor authentication to reduce the impact of credential theft resulting from spoofing attacks.