Microsoft has disclosed two critical vulnerabilities in its Windows BitLocker encryption feature, allowing attackers with physical access to bypass security protections and access encrypted data.
Released on October 14, 2025, as part of the latest Patch Tuesday updates, these flaws, tracked as CVE-2025-55338 and CVE-2025-55333, pose a significant risk to users relying on BitLocker for full-disk encryption on Windows devices.
Both vulnerabilities carry an “Important” severity rating and a CVSS v3.1 base score of 6.1, highlighting the potential for high-impact data breaches in scenarios involving device theft or tampering.
BitLocker, a built-in Windows tool designed to encrypt entire drives and protect sensitive information, has long been a cornerstone of enterprise and personal security.
However, these new issues stem from flaws in how the system handles ROM code patching and data comparisons, enabling unauthorized access without needing passwords or recovery keys.
For CVE-2025-55338, the problem lies in the missing ability to patch ROM code, which leaves a gap for physical attacks. Similarly, CVE-2025-55333 involves an incomplete comparison mechanism that fails to account for key factors, as defined under CWE-1023.
In both cases, an attacker could exploit the weaknesses to decrypt the system storage device, exposing confidential files, user credentials, and potentially corporate secrets.
Understanding The Attack Vector
These vulnerabilities require physical proximity to the target device, making them particularly relevant for scenarios like laptop theft or insider threats.
According to Microsoft’s analysis, exploitation involves low complexity with no user interaction or privileges needed, but the unchanged scope limits broader network propagation.
The vector string for both is CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N, emphasizing high confidentiality and integrity impacts while availability remains unaffected.
Microsoft assesses exploitation as “less likely” since the flaws were not publicly disclosed prior to patching, and no active exploits have been observed.
Still, the official fix available through Windows Update urges immediate application, especially for mobile workers or those in high-risk environments.
| CVE ID | Description | CVSS Base Score | Attack Vector | Severity | Weakness |
|---|---|---|---|---|---|
| CVE-2025-55338 | Missing ROM code patching | 6.1 | Physical | Important | N/A |
| CVE-2025-55333 | Incomplete comparison with missing factors | 6.1 | Physical | Important | CWE-1023 |
Mitigations
The discovery of these issues by Alon Leviev from Microsoft’s Security Threat Operations and Response Management (STORM) team highlights ongoing efforts to fortify core OS components.
While not as devastating as remote code execution bugs, they remind users that physical security remains vital; no encryption is foolproof without safeguards like TPM modules and strong access controls.
Organizations should prioritize patching affected Windows 10 and 11 systems, conduct device audits, and consider multi-factor authentication for recovery options.
As cyber threats evolve, these vulnerabilities serve as a wake-up call to integrate BitLocker with layered defenses, ensuring data stays protected even in the hands of adversaries.
Microsoft recommends enabling automatic updates and monitoring for unusual physical access attempts to mitigate risks effectively.
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