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 potentially undermine the integrity of the operating system and bypass security features that are meant to protect the system from deep-level persistent threats.
Technical details
A protection mechanism failure (CWE-693) exists in the Windows Secure Boot implementation. An attacker with local access and administrative (High) privileges can exploit this vulnerability to bypass Secure Boot integrity checks. The vulnerability is characterized by a Scope change (S:C) in the CVSS metric, indicating that the exploit allows the attacker to bypass a security boundary maintained by the firmware or hardware. This could lead to the execution of unsigned or malicious boot-level code. Microsoft has released information regarding this vulnerability via their Security Update Guide.
Affected products
- Microsoft Windows
Timeline
- 2026-06-09: disclosed
- 2026-06-09: advisory