cve-2026-45654

CVE-2026-45654 is a Microsoft-disclosed Secure Boot security feature bypass affecting Windows 11 24H2, 25H2, 26H1, and Windows Server 2025. Rated Important, the flaw was addressed in the June 9, 2026 Patch Tuesday cumulative updates. Microsoft assesses exploitation as less likely and has not observed active exploitation. The vulnerability sits at the intersection of firmware trust, Windows boot integrity, and secrets protected by virtualization-based security (VBS). Discussions on WindowsForum highlight concerns about recurring Secure Boot issues in this high-consequence area. Users should apply the June 2026 updates to mitigate the risk.