Executive brief
A security flaw in Windows Secure Boot could allow an attacker with administrative privileges to bypass critical boot-time protections. Secure Boot is designed to ensure that a computer starts using only software that is trusted by the manufacturer. If exploited, an attacker could undermine the integrity of the operating system, potentially allowing for the installation of persistent malware that survives system reboots and remains hidden from standard security tools.
Technical details
A protection mechanism failure exists in the Windows Secure Boot implementation, categorized as a reliance on a component that is not updateable (CWE-1329). An attacker with local access and administrative or high-level privileges can exploit this vulnerability to bypass Secure Boot integrity checks. Because the vulnerability involves a 'Scope Change' (S:C) in the CVSS metric, the exploit allows the attacker to impact components beyond the immediate security scope of the operating system's kernel. This could lead to the execution of unsigned or malicious bootloaders. Microsoft has released information regarding this vulnerability via their Security Update Guide.
Affected products
- Microsoft Windows
Timeline
- 2026-06-09: disclosed: Initial publication by Microsoft and NVD.
- 2026-06-09: advisory: Microsoft MSRC advisory published.