CVE-2025-26637 is a vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting the BitLocker encryption feature. BitLocker is designed to protect data by providing encryption for entire volumes, thereby preventing unauthorized access to data on lost or stolen devices. The vulnerability is categorized under CWE-693, which relates to protection mechanism failures. In this case, the flaw allows an unauthorized attacker to bypass BitLocker's security protections through a physical attack on the device. The attack vector requires physical access (AV:P), but does not require any privileges or user interaction (PR:N/UI:N). The vulnerability impacts confidentiality, integrity, and availability of the protected data, as an attacker can potentially decrypt or manipulate encrypted volumes. The CVSS v3.1 base score is 6.8, indicating a medium severity level. The vulnerability does not currently have known exploits in the wild, and no patches have been linked yet. The issue arises from a failure in the protection mechanism of BitLocker, which may involve weaknesses in key management, hardware integration, or cryptographic enforcement that can be exploited physically, such as through direct hardware manipulation or cold boot attacks. Since Windows 10 Version 1809 is an older release, this vulnerability highlights the risks of continued use of legacy operating systems without up-to-date security patches or mitigations.

For European organizations, this vulnerability poses a significant risk to data confidentiality and integrity, especially for entities relying on BitLocker for endpoint encryption on Windows 10 Version 1809 devices. Organizations in sectors such as finance, healthcare, government, and critical infrastructure that handle sensitive personal or proprietary data could face data breaches if attackers gain physical access to devices. The ability to bypass BitLocker protections could lead to unauthorized data disclosure, data tampering, or disruption of services. This is particularly concerning for mobile or remote workforce devices that may be lost or stolen. Additionally, the impact extends to regulatory compliance, as unauthorized data exposure could violate GDPR and other data protection laws, resulting in legal and financial penalties. The lack of known exploits in the wild suggests that the threat is currently theoretical or limited, but the medium severity rating and physical attack vector mean that attackers with physical access and technical capability could exploit this vulnerability. Organizations with legacy Windows 10 Version 1809 deployments are at higher risk, especially if they have not applied mitigations or upgraded to supported versions.

1. Upgrade affected systems to a newer, supported version of Windows 10 or Windows 11 where this vulnerability is addressed. 2. Enforce strict physical security controls to prevent unauthorized physical access to devices, including secure storage, access logging, and surveillance. 3. Implement multi-factor authentication for device startup (e.g., TPM with PIN or USB key) to add an additional layer of protection beyond BitLocker alone. 4. Regularly audit and inventory devices running Windows 10 Version 1809 and prioritize their replacement or upgrade. 5. Use hardware-based security features such as TPM 2.0 and ensure firmware is up to date to reduce attack surface. 6. Employ endpoint detection and response (EDR) solutions to monitor for suspicious activity that may indicate attempts to exploit physical vulnerabilities. 7. Educate employees on the risks of device theft and the importance of reporting lost or stolen devices promptly. 8. Consider full disk encryption alternatives or complementary encryption solutions that provide defense in depth. 9. Monitor official Microsoft advisories for patches or updates addressing this vulnerability and apply them promptly once available.