CVE-2025-55333 is a vulnerability identified in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0) specifically affecting the BitLocker full disk encryption feature. The root cause is an incomplete comparison operation within BitLocker’s security mechanism, classified under CWE-1023 (Incomplete Comparison with Missing Factors). This flaw allows an attacker who has physical access to a device to bypass BitLocker’s encryption protections, potentially gaining unauthorized access to encrypted data. The vulnerability does not require any privileges or user interaction, making it a direct physical attack vector. However, the attack is constrained by the need for physical access, limiting remote exploitation possibilities. The CVSS v3.1 base score is 6.1, indicating medium severity, with a vector string AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C. This means the attack requires physical access (AV:P), has low attack complexity (AC:L), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality and integrity highly (C:H/I:H) but does not affect availability (A:N). The exploitability is currently theoretical, with no known exploits in the wild and no patches published yet. The vulnerability’s impact is significant for data confidentiality and integrity on affected devices, especially portable endpoints that rely on BitLocker for data protection. Organizations relying on BitLocker as a primary encryption method should be aware of this risk and prepare mitigation strategies accordingly.

For European organizations, this vulnerability poses a risk primarily to the confidentiality and integrity of sensitive data stored on Windows 11 Version 25H2 devices protected by BitLocker. Since the attack requires physical access, organizations with mobile or remote workforce devices, such as laptops or tablets, are particularly vulnerable. The potential impact includes unauthorized data disclosure and tampering, which could lead to data breaches, regulatory non-compliance (e.g., GDPR violations), and loss of trust. Critical sectors such as finance, healthcare, government, and infrastructure that rely heavily on endpoint encryption for data protection could face significant operational and reputational damage if devices are compromised. The lack of a patch increases the urgency for interim mitigations. The vulnerability does not affect availability, so service disruption is unlikely, but the breach of confidentiality and integrity can have long-term consequences. Organizations with strong physical security controls may mitigate risk, but those with less controlled environments or high device mobility face elevated exposure.

1. Enhance physical security controls to prevent unauthorized physical access to devices, including secure storage, access badges, and surveillance. 2. Implement strict device handling policies, especially for laptops and portable devices, including encryption key management and device tracking. 3. Use multi-factor authentication for device access where possible to add an additional layer beyond BitLocker. 4. Monitor for unusual device access or tampering attempts through endpoint detection and response (EDR) solutions. 5. Limit the use of Windows 11 Version 25H2 on devices handling highly sensitive data until a patch is released. 6. Regularly back up critical data to secure, offline storage to mitigate data loss risks. 7. Educate users on the importance of physical device security and reporting lost or stolen devices immediately. 8. Stay informed on Microsoft’s updates and apply patches promptly once available. 9. Consider alternative encryption solutions or layered encryption approaches for high-risk environments. 10. Conduct regular security audits focusing on physical security and encryption effectiveness.