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Microsoft released Windows 11 cumulative update KB5124008 for versions 24H2 and 25H2 (OS builds 26100.9445 and 26200.9445), expanding high-confidence device targeting for automatic deployment of replacement Secure Boot certificates. The rollout addresses the expiration of 2011-era Microsoft Secure Boot certificates: the KEK CA and UEFI CA expired in June 2026, and the Windows Production PCA certificate expires on October 19, 2026. The update also includes servicing stack update KB5124007, security and reliability fixes, and updated AI components for Copilot+ PCs.
Organizations and users should keep Windows Update enabled, apply applicable OEM firmware or BIOS updates, and verify that Secure Boot remains enabled in Windows Security. Microsoft said devices awaiting replacement certificates should continue to boot and receive regular Windows updates during the staged deployment. Administrators using Dynamic Update packages must include the version- and architecture-matched boot.stl file in installation media to prevent potential boot failures; Microsoft reported no known issues with KB5124008.
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Microsoft released the Windows 11 cumulative update KB5124008 (OS Builds 26200.9445 and 26100.9445), expanding high-confidence targeting data so more eligible devices can automatically receive replacement Secure Boot certificates. The update also included servicing stack update KB5124007 and reliability and usability fixes.
Microsoft's UEFI CA 2011 Secure Boot certificate expired. It had been used to sign third-party boot loaders, EFI applications, and some option ROMs.
Microsoft's Corporation KEK CA 2011 Secure Boot certificate expired. The certificate had been used to sign updates to Secure Boot's allowed and revoked signature databases, DB and DBX.
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Microsoft began **automatically replacing expiring Secure Boot certificates** on eligible **Windows 11 24H2 and 25H2** devices via Windows quality updates, using a phased rollout that targets “high-confidence” devices based on successful update signals. The change follows earlier warnings that commonly used Secure Boot trust anchors will start expiring in **June 2026**, which could disrupt secure boot validation on UEFI systems if not remediated. Secure Boot relies on firmware-stored certificates to verify bootloader signatures and prevent pre-boot malware (e.g., rootkits) from loading. Microsoft warned that failing to update these certificates can lead to loss of **Windows Boot Manager trust** and **Secure Boot protections**, and may prevent devices from receiving future security updates for pre-boot components—creating both availability and security risk. For organizations that need tighter control, Microsoft also provides **manual deployment options** (e.g., via registry-based methods and enterprise management tooling such as policy/configuration controls) to ensure certificate updates are applied ahead of expiration and to validate Secure Boot status across fleets.
Jun 29, 2026
Microsoft began rolling out **Windows 11 preview updates** for versions **25H2 and 24H2** (including the optional non-security preview update `KB5074105` and Release Preview builds `26200.7701`/`26100.7701`) focused on functionality, performance, and reliability improvements rather than patching new security vulnerabilities. The updates emphasize expanded **AI-driven experiences** (including refinements to Copilot+ PC-related models and more natural-language assistance within Settings), along with usability changes and a simplified Windows update title format intended to reduce administrative friction in tools like **WSUS** and **Microsoft Configuration Manager**. Alongside these feature updates, Microsoft highlighted an operational security risk: **Windows Secure Boot certificates** used by most Windows devices are expected to begin expiring in **June 2026**, and organizations that do not update Certificate Authority (CA) material in time may face devices that cannot boot securely. Separately, consumer guidance circulated on bypassing Windows 11 hardware eligibility checks (notably **TPM 2.0** requirements) to upgrade “unsupported” PCs; while this may extend device usability after Windows 10 support ended, it can also undermine Microsoft’s intended security baseline and increase enterprise risk if adopted outside controlled policy.
Jun 29, 2026
Microsoft released the June cumulative update `KB5093998` for Windows 11 23H2 with security fixes, broader Secure Boot certificate rollout support, and a new Group Policy/MDM option to limit Secure Boot service data sent to Microsoft. The update also fixes a known issue that could force some devices into **BitLocker Recovery** after boot file updates, while CERT/CC and Microsoft separately published advisories on a Secure Boot bypass affecting Microsoft-signed UEFI shim bootloaders, tracked as `CVE-2026-44815`. At the same time, Microsoft warned that some PCs upgraded from Windows 10 21H2/22H2 or Windows 11 23H2 to Windows 11 24H2 or 25H2 may fail to install the June 2026 cumulative updates, showing errors `0x80073712` or `0x800f0993` because of package and component store issues. Microsoft said an automatic fix is rolling out for unmanaged enterprise and Home devices after restart, while already affected systems may require removing a problematic package with DISM or performing an in-place upgrade; separate reporting also said recent HP BIOS updates and Dell SupportAssist software caused BitLocker loops and BSODs that were initially blamed on Windows but traced to OEM firmware and utilities.
Jun 29, 2026