CVE-2025-21214 is a medium-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) that involves the exposure of sensitive information related to BitLocker, Microsoft's full disk encryption feature. The vulnerability is classified under CWE-200, which corresponds to the exposure of sensitive information to unauthorized actors. BitLocker is designed to protect data confidentiality by encrypting entire volumes, and any leakage of BitLocker-related information could potentially aid attackers in circumventing encryption protections or gaining insights into encrypted data. The CVSS 3.1 base score is 4.2, indicating a medium impact primarily on confidentiality (C:H), with no impact on integrity or availability. The attack vector is physical (AV:P), requiring high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The scope is unchanged (S:U), meaning the vulnerability affects only the vulnerable component without impacting other components. The exploitability is limited due to the physical access requirement and high complexity, and there are no known exploits in the wild as of the publication date (January 14, 2025). No official patches or mitigation links have been provided yet. This vulnerability could allow an attacker with physical access to a device running Windows 10 Version 1809 to extract sensitive BitLocker information, potentially aiding in offline attacks against encrypted volumes or revealing encryption keys or metadata that should remain confidential.

For European organizations, the exposure of BitLocker information could undermine the confidentiality guarantees of encrypted data on laptops, desktops, and mobile devices running Windows 10 Version 1809. This is particularly concerning for sectors handling sensitive personal data under GDPR, such as healthcare, finance, and government agencies. Although exploitation requires physical access and is complex, the risk remains significant in environments where devices may be lost, stolen, or accessed by unauthorized personnel. The leakage of BitLocker-related information could facilitate data breaches, regulatory non-compliance, and reputational damage. Organizations relying on BitLocker for endpoint encryption must consider the potential for attackers to gain insights that weaken encryption protections, increasing the risk of data exposure. The vulnerability does not affect system integrity or availability, but the confidentiality impact alone warrants attention, especially for organizations with strict data protection requirements.

Given the absence of an official patch, European organizations should implement layered mitigations: 1) Enforce strict physical security controls to prevent unauthorized access to devices, including secure storage and access logging. 2) Upgrade affected systems from Windows 10 Version 1809 to a supported, patched version of Windows where this vulnerability is resolved. 3) Use additional encryption layers or hardware security modules (e.g., TPM with PIN or USB key requirements) to strengthen BitLocker protections. 4) Employ endpoint detection and response (EDR) solutions to monitor for suspicious physical access or attempts to extract encryption-related information. 5) Conduct regular audits of device encryption status and ensure recovery keys are securely stored and managed. 6) Educate employees on the risks of device loss or theft and enforce policies for immediate reporting and response. These steps go beyond generic advice by focusing on physical security, system upgrades, and enhanced encryption management tailored to this vulnerability's characteristics.