CVE-2026-20962 is a vulnerability classified under CWE-908 (Use of Uninitialized Resource) affecting Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The flaw resides in the Dynamic Root of Trust for Measurement (DRTM) mechanism, a security feature designed to establish a trusted computing base by measuring system components during boot or runtime to ensure integrity. The vulnerability arises because an internal resource within DRTM is used without proper initialization, potentially leaking sensitive information to an attacker. The attacker must have authorized local access with high privileges (PR:H) but does not require user interaction (UI:N). The vulnerability impacts confidentiality (C:H) but does not affect integrity (I:N) or availability (A:N). The attack vector is local (AV:L), and the attack complexity is low (AC:L), meaning that once local privileged access is obtained, exploitation is straightforward. The scope is unchanged (S:U), indicating the impact is limited to the vulnerable component without affecting other system components. No known exploits are currently reported in the wild, and no official patches have been released at the time of publication. The vulnerability was reserved in December 2025 and published in January 2026. Given the nature of DRTM, which is critical for trusted computing, leakage of information could undermine system security assurances and potentially aid further attacks. However, the requirement for high privileges and local access limits the immediate risk to remote attackers or unprivileged users.

For European organizations, this vulnerability poses a risk primarily to confidentiality of sensitive information on systems running Windows 11 Version 25H2. Organizations with high-value intellectual property, personal data, or regulated information could face data leakage if attackers gain privileged local access. Sectors such as finance, healthcare, government, and critical infrastructure are particularly sensitive to such leaks. Although the vulnerability does not allow remote exploitation or system disruption, the potential for information disclosure could facilitate lateral movement or privilege escalation in targeted attacks. The requirement for local high privileges means that insider threats or attackers who have already compromised a system could leverage this vulnerability to gain additional intelligence. This could undermine trust in the platform’s security features, especially in environments relying on DRTM for secure boot and trusted execution. European organizations should be aware of this vulnerability as part of their risk management and incident response planning, especially those with extensive Windows 11 deployments and stringent compliance requirements.

1. Restrict and monitor administrative and privileged local access to Windows 11 systems, ensuring only trusted personnel have such rights. 2. Implement robust endpoint detection and response (EDR) solutions to detect unusual local privilege escalations or suspicious activity related to DRTM components. 3. Enforce strict access controls and use multi-factor authentication for administrative accounts to reduce the risk of credential compromise. 4. Maintain up-to-date inventory of Windows 11 Version 25H2 deployments to identify affected systems promptly. 5. Prepare for rapid deployment of official patches or updates from Microsoft once released; subscribe to vendor security advisories. 6. Employ application whitelisting and system hardening to reduce the attack surface and prevent unauthorized code execution. 7. Conduct regular security audits and penetration testing focusing on privilege escalation and information disclosure vectors. 8. Educate IT staff and users about the risks of privilege misuse and the importance of reporting suspicious behavior. These measures go beyond generic advice by focusing on controlling privileged local access and preparing for patch management specific to this vulnerability.