CVE-2025-55334 is a vulnerability classified under CWE-312, indicating cleartext storage of sensitive information. It affects Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The flaw resides in the Windows Kernel, where sensitive information is stored in cleartext rather than being encrypted or otherwise protected. This improper handling allows an unauthorized local attacker to bypass security features by directly accessing this sensitive data. The vulnerability does not require any privileges or user interaction, making it easier to exploit for anyone with local access to the affected system. However, the attack vector is limited to local access, which reduces the overall risk of remote exploitation. The CVSS v3.1 base score is 6.2 (medium severity), reflecting high confidentiality impact but no impact on integrity or availability. No known exploits have been reported in the wild, and no patches have been released yet. The vulnerability could be leveraged to extract sensitive credentials or security tokens, potentially enabling further local privilege escalation or lateral movement within a network. The lack of encryption or secure storage mechanisms for sensitive kernel data is a critical design flaw that Microsoft needs to address promptly.

For European organizations, the primary impact of CVE-2025-55334 is the compromise of confidentiality of sensitive information stored on Windows 11 endpoints. This could include credentials, security tokens, or other sensitive kernel data that, if accessed, might facilitate further attacks such as privilege escalation or unauthorized access to internal resources. Organizations with high-value data or critical infrastructure running Windows 11 25H2 are at greater risk. The vulnerability does not directly affect system integrity or availability, so service disruption is unlikely. However, the potential for data leakage could lead to regulatory compliance issues under GDPR, reputational damage, and increased risk of subsequent attacks. Since exploitation requires local access, the threat is more significant in environments where endpoint physical or remote access controls are weak, such as shared workstations or poorly secured remote desktop environments.

Currently, no official patches are available for CVE-2025-55334, so organizations should implement compensating controls. These include enforcing strict local access controls and user account management to limit who can log into Windows 11 25H2 systems. Employ endpoint detection and response (EDR) tools to monitor for suspicious local activity indicative of attempts to access kernel memory or sensitive data. Use full disk encryption and secure boot features to reduce the risk of unauthorized physical access. Restrict use of shared or guest accounts and disable unnecessary local accounts. Once Microsoft releases a patch, prioritize its deployment across all affected systems. Additionally, conduct regular audits of local access logs and educate users about the risks of leaving devices unattended. Consider network segmentation to isolate critical systems and reduce the risk of lateral movement if credentials are compromised.