cve 2026 58638

The cve 2026 58638 tag covers Microsoft’s July 14, 2026 security update for a Windows Boot Loader security feature bypass. The vulnerability affects supported Windows client and server releases, including Windows 10 version 1809 through Windows 11 version 26H1 and Windows Server 2025. Microsoft describes the issue as a missing cryptographic step that could allow a locally authorized attacker to bypass a security feature. Coverage focuses on deploying the July cumulative updates and applying the corresponding boot-component updates to offline installation media, recovery environments, and related deployment workflows. These steps help ensure updated systems and recovery processes receive the intended boot loader protection.