CVE-2025-48818 is a vulnerability classified as a CWE-367 TOCTOU race condition affecting Microsoft Windows 10 Version 1507 (build 10.0.10240.0), specifically targeting the BitLocker encryption feature. A TOCTOU race condition occurs when a system checks a condition and then uses the result of that check later, but the state changes in between, allowing an attacker to exploit the timing gap. In this case, an unauthorized attacker with physical access can exploit the timing window between the time BitLocker checks the integrity or authorization of a security-critical operation and the time it actually uses the data or key material. This can lead to bypassing BitLocker’s encryption protections, potentially exposing sensitive data or allowing unauthorized system modifications. The vulnerability has a CVSS 3.1 base score of 6.8, reflecting medium severity, with attack vector being physical (AV:P), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits have been reported in the wild, and no official patches have been released as of the publication date. The affected product is an early Windows 10 release (Version 1507), which is largely out of support, increasing the risk for organizations still running this version. The vulnerability’s exploitation requires physical access, making remote exploitation infeasible, but physical attacks on devices in unprotected environments are possible. This vulnerability highlights the importance of secure handling of cryptographic operations and race condition mitigation in security-critical software components.

For European organizations, the impact of CVE-2025-48818 can be significant if they continue to use Windows 10 Version 1507 with BitLocker enabled. Successful exploitation allows attackers to bypass BitLocker encryption, potentially exposing sensitive corporate or personal data, violating data protection regulations such as GDPR. This can lead to data breaches, loss of intellectual property, and reputational damage. The integrity and availability of systems can also be compromised, allowing unauthorized modifications or denial of access. Since the attack requires physical access, organizations with inadequate physical security controls—such as those with remote or unattended devices—are at higher risk. Critical sectors like finance, healthcare, and government, which rely heavily on data confidentiality and integrity, could face severe consequences. Additionally, the lack of patches means organizations must rely on compensating controls until they upgrade to supported Windows versions. The medium severity rating reflects the balance between high impact and limited exploitability due to physical access requirements.

1. Upgrade all affected systems from Windows 10 Version 1507 to a supported and patched Windows version to eliminate the vulnerability. 2. Enforce strict physical security controls to prevent unauthorized physical access to devices, including secure storage, access logging, and surveillance. 3. Implement full disk encryption solutions that are up-to-date and have no known TOCTOU vulnerabilities. 4. Use hardware-based security modules (e.g., TPM chips) properly configured to enhance BitLocker protection. 5. Regularly audit and monitor physical access to critical devices, especially in shared or public environments. 6. Educate employees about the risks of leaving devices unattended and the importance of physical security. 7. If upgrading immediately is not feasible, consider disabling BitLocker temporarily or using alternative encryption until patched versions are deployed. 8. Maintain an inventory of devices running the vulnerable Windows version to prioritize remediation efforts. 9. Monitor security advisories from Microsoft for patches or workarounds related to this vulnerability. 10. Employ endpoint detection and response (EDR) tools to detect suspicious activities that may indicate exploitation attempts.