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Microsoft issued a Secure Boot playbook telling organizations to update Windows and firmware trust chains before older Secure Boot certificates begin expiring in June 2026. The guidance says Secure Boot relies on CA-backed keys in UEFI firmware to validate trusted boot components and reduce exposure to early-boot malware, and ties the certificate refresh to protections against the BlackLotus bootkit issue tracked as CVE-2023-24932. Microsoft said many PCs built since 2024 already include the newer 2023 certificates, while other systems may need monthly Windows updates, OEM BIOS/UEFI updates, or both. The company recommended a phased rollout that starts with device inventory and Secure Boot status checks, then pilots updates and validates success through registry keys and Windows Event Log indicators.
Enterprise administrators reported that Windows updates alone may not be sufficient on all hardware, particularly for Lenovo and other systems that still require vendor firmware updates to ensure compatibility and load the new certificates into UEFI defaults. Practitioners also warned that automatic certificate deployment can depend on factors such as firmware readiness, telemetry, and whether devices fall into Microsoft's higher-confidence rollout groups. Operational concerns raised include multiple reboot cycles, possible BitLocker impacts, scheduled task triggers, and the need to update related Secure Boot-dependent assets including servers, virtual machines, PXE images, and recovery media.
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4 events from the most recent confirmed update back to the earliest known activity.
Microsoft published a Windows IT Pro Blog post advising organizations to update Windows Secure Boot certificate authorities before older certificates begin expiring. The playbook describes deployment methods, validation steps, troubleshooting guidance, and the need for OEM firmware updates where required.
Microsoft stated that many Windows PCs manufactured since 2024 already include the updated 2023 Secure Boot certificates, reducing the need for later remediation on those devices.
Microsoft said the updated Secure Boot certificates are a security measure to address the BlackLotus UEFI bootkit vulnerability tracked as CVE-2023-24932.
Microsoft said older Secure Boot certificates begin expiring in June 2026 and urged organizations to install the 2023 certificate authorities before the 2011 CAs expire.
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Microsoft warned that Secure Boot certificates issued in 2011 are nearing expiration and that devices which do not receive the newer 2023 Secure Boot update will generally keep booting, but may stop receiving future boot-chain protections. The gap affects some older Windows systems whose OEMs no longer provide compatible BIOS or UEFI updates, as well as devices running Legacy BIOS, CSM mode, or unsupported Windows 11 configurations with Secure Boot disabled. Microsoft is reportedly skipping incompatible hardware rather than forcing updates that could cause failures, but enterprises may still face compliance, cyber-insurance, and lifecycle-management pressure because those endpoints could miss future `DBX` revocations, Windows Boot Manager updates, and mitigations for bootloader threats such as **BlackLotus**. The transition is also creating planning challenges beyond Windows. Linux distributions that rely on Microsoft-signed **shim** loaders are expected to continue booting on systems that already trust the older Microsoft UEFI CA, but older PCs that never receive firmware updates with the 2023 certificates may have trouble booting newer Linux media or releases. The issue follows Microsoft's broader effort to harden the pre-boot environment after flaws such as `CVE-2024-21302`, a Windows Secure Kernel Mode elevation-of-privilege bug that could let an administrator roll back VBS-related files to bypass protections; Microsoft responded with boot-time code integrity policies, an optional `SkuSiPolicy.p7b` revocation policy, and stronger protections on newer Windows releases. Administrators are being urged to verify Secure Boot update status, update firmware and recovery media where possible, and document compensating controls or replace hardware that cannot be brought forward.
Jun 29, 2026
Microsoft has started deploying updated **Secure Boot** certificates via regular monthly Windows updates to replace the original 2011-era certificates that begin expiring in **late June 2026**. Secure Boot, introduced in 2011 for UEFI-based systems, helps prevent pre-OS malware (e.g., bootkits/rootkits) by allowing only trusted, properly signed boot components to load, using a certificate chain anchored in UEFI firmware and validated against trusted signature databases. The expiring components include Microsoft-issued certificates used in the Secure Boot trust chain (including the **Key Exchange Key (KEK)** and Microsoft **UEFI CA/Production CA** certificates), which are present on most PCs built since 2011 and also affect many Linux distributions that rely on Microsoft’s UEFI signing ecosystem. Microsoft says the refresh will be automatic for in-support Windows devices where updates are Microsoft-managed, while organizations can also control deployment through their own management tooling; the effort is positioned as a large-scale ecosystem maintenance activity involving coordination across many OEM firmware configurations.
Jun 29, 2026
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