SecureBoot Archives

Winsage

July 18, 2026

Windows 11 Secure Boot certificates have expired, and Microsoft says what to do next

Microsoft held its OEM Secure Boot Office Hours event on July 15, where engineers collaborated with OEM representatives from companies like Acer, Asus, Cisco, Dell, and HP. IT administrators were able to ask live questions about the Secure Boot 2023 rollout. The discussion thread became a detailed technical record, especially following the expiration of the first certificates three weeks prior. Concerns raised by IT admins included BitLocker recovery loops, stuck confidence ratings, and unhelpful Intune error codes. Key facts include: - Devices offline for long periods will still receive the 2023 certificates upon reconnecting to Windows Update. - Devices with existing 2023 certificates in firmware will switch to the new boot manager after the latest Windows patches are installed. - A new script, Detect-SecureBootCertUpdateStatus.ps1, is available in Windows for checking certificate status. - BIOS updates may reset a device’s confidence rating to unrated, which is normal and does not indicate certificate failure. - Admins should edit the AvailableUpdates registry key, not the AvailableUpdatesPolicy, which is managed by Intune and Group Policy. - A licensing bug affecting AvailableUpdatesPolicy on devices upgraded from Pro to Enterprise was resolved by Microsoft in 2026. - BitLocker recovery is not typically linked to the certificate update process but may relate to firmware or PCR issues. - Dell and HP provided guidance on which BIOS versions include the 2023 certificates for their newer models. - Older HP EliteBook 840 G5 units require a manual update package for the new certificates. - Eligible devices can still receive the 2023 certificates in the future, and Surface devices released from 2024 onward come pre-equipped with them. - Microsoft confirmed that devices running 2011 certificates will not lose the ability to receive the 2023 chain. - The Microsoft Corporation KEK CA 2011 and Microsoft UEFI CA 2011 certificates have expired, with the Microsoft Windows Production PCA 2011 set to expire on October 19, 2026.

Winsage

June 25, 2026

Windows 11 Secure Boot update released to all, hours ahead of expiry

Microsoft has begun rolling out the Secure Boot 2023 certificate update to eligible Windows 11 and Windows 10 PCs ahead of the expiration of the Microsoft Corporation KEK CA 2011 on June 24, 2026. This update enhances device targeting data for automatic Secure Boot certificate updates. Secure Boot is a firmware-level security feature that verifies digital signatures of boot components to prevent rootkits and bootkits. The certificates for Secure Boot were first issued in 2011, with subsequent expirations for related certificates occurring in June and October 2026. Users can check their Secure Boot certificate status through the Windows Security app or System Information. If a PC does not receive the update, it will still boot normally but will lose the ability to receive future boot-level security updates. Multiple restarts after updates are expected due to the Secure Boot certificate process. A new folder, C:WindowsSecureBoot, is not malware but is used for staging cryptographic certificate files. Windows 10 users enrolled in the Extended Security Updates program will also receive the Secure Boot update, while those not enrolled will not. The expiration of the KEK CA 2011 means Microsoft will not be able to sign new Secure Boot revocation payloads using the old key, but existing signed payloads will remain functional.

Winsage

June 24, 2026

Windows 11 Secure Boot update released to all, hours ahead of expiry

Microsoft has begun rolling out the Secure Boot 2023 certificate update for eligible Windows 11 and Windows 10 PCs ahead of the expiration of the original certificates on June 24, 2026. The update includes additional device targeting data to increase coverage for automatic updates. Devices receive the new certificates after demonstrating successful update signals. The original Secure Boot certificates were issued in 2011, with expiration dates set for June 24, 2026, June 27, 2026, and October 19, 2026. Microsoft has been distributing replacement 2023 certificates since 2024, with the June 2026 update expanding eligible devices significantly. Users can check their Secure Boot status through the Windows Security app or System Information. If a PC did not receive the update, it will still function normally but may not receive future boot-level security updates. Multiple restarts after updates are expected behavior, and the SecureBoot folder in Windows is not malware. Windows 10 users in the Extended Security Updates program are also receiving the Secure Boot update. The expiration of the Microsoft Corporation KEK CA 2011 on June 24 means no new Secure Boot revocation payloads can be signed with the old key, but existing signed payloads will continue to function.

Winsage

June 15, 2026

Microsoft released the Windows 11 Secure Boot update for all PCs, how to verify yours

Microsoft has expanded the rollout of the Secure Boot 2023 certificate update to more Windows 11 and Windows 10 devices with the June 2026 Patch Tuesday update (KB5094126). This update aims to ensure that most supported consumer PCs are classified as high confidence, meaning necessary certificates are either installed or will be applied automatically. Secure Boot is a firmware security feature that verifies the software attempting to load during the startup process, blocking unauthorized software. The certificates supporting Secure Boot, issued in 2011, are expiring in stages starting June 24, 2026, prompting Microsoft to deploy replacement certificates. Most home users do not need to take manual action as the updates will occur automatically via Windows Update. Users can check their Secure Boot certificate status in the Windows Security app. A yellow warning indicates pending compatibility data, while a red alert suggests a firmware incompatibility requiring a BIOS update. Multiple reboots during the update process are normal, and a new SecureBoot folder in Windows is for staging cryptographic files. Older PCs may experience longer update times, and some may not receive updates due to firmware issues. HP users should check for BIOS updates if encountering BitLocker recovery loops. IT administrators should monitor device classifications and manually initiate updates for devices not in the high confidence category. Devices with Secure Boot disabled cannot receive updates, leaving them vulnerable. The expiration of the Microsoft Corporation KEK CA 2011 certificate on June 24 does not immediately affect device functionality, but it limits Microsoft's ability to sign new bootkit blacklist updates.

Winsage

May 28, 2026

Your Windows PC has a security deadline in June 2026

A Secure Boot certificate refresh is being deployed across supported Windows devices via Windows Update. The Secure Boot certificates from 2011 will begin to expire in June 2026, prompting Microsoft to introduce new 2023-dated certificates to maintain security. Most users will require minimal action if their PCs are updated, but older devices may face challenges. The current certificates include: - Microsoft Corporation KEK CA 2011: expires June 24, 2026 - Microsoft UEFI CA 2011: expires June 27, 2026 - Microsoft Windows Production PCA 2011: expires October 19, 2026 The new certificates will remain valid until 2038, with plans for post-quantum cryptography around 2030. While PCs using the 2011 certificates will continue to function, they will lose access to new security protections, making them vulnerable to emerging threats. A notable example of such a threat is the BlackLotus bootkit, which exploited vulnerabilities to bypass Secure Boot. Microsoft's rollout strategy involves a staged update process that typically takes around 48 hours and may require restarts. Users are advised to keep Windows updated and check their Secure Boot status. Known issues may arise for older PCs, systems that bypassed Windows 11 requirements, Legacy BIOS systems, and custom firmware configurations. IT teams managing devices should inventory their systems, monitor specific event IDs, test updates, and document devices that cannot be updated.

Winsage

May 28, 2026

Windows Server 2016 Update: Disastrous Bug Breaks AD

Microsoft released a mandatory patch (KB5087537) for Windows Server 2016 to enhance cryptographic layers and address critical vulnerabilities. This update is essential for organizations using legacy workloads, as mainstream support ended in January 2022, but extended support continues until January 12, 2027. The patch aims to prepare systems for the expiration of Windows Secure Boot certificates in June 2026, which, if not updated, could compromise security and expose systems to malware. The update uses a phased deployment model and includes a new SecureBoot folder to assist IT professionals in managing certificate status. It also addresses various quality-of-life issues, including bugs affecting Remote Desktop Connection and authentication errors with Microsoft services. However, a significant issue arises when the host server name is exactly 15 characters long, causing failures in the domain controller discovery process and obstructing critical operations. This bug is linked to the historical 15-character limit of NetBIOS, which affects the Active Directory lookup mechanism. Microsoft has acknowledged the issue but has not provided a timeline for a fix, leaving administrators to either rename servers or uninstall the update. As the Secure Boot deadline approaches, IT departments must carefully assess their environments to avoid disruptions while ensuring security compliance.

Winsage

May 21, 2026

Windows 11’s new SecureBoot folder isn’t malware. Here’s what it does

Users have observed a new folder named “SecureBoot” in the Windows system folder following the installation of Windows 11's May update (KB5089549). This update may cause installation issues for some devices and introduces a directory that contains example scripts for IT professionals to manage Secure Boot certificate updates. Windows Secure Boot certificates are set to expire next month, and outdated certificates will lead to loss of support starting in June, potentially compromising Secure Boot functionality. Microsoft is distributing new certificates through Windows Update. The SecureBoot folder does not require individual users to take action, and deleting it is discouraged as it may cause complications with future Windows updates.

Winsage

June 12, 2025

UEFI BIOS flaws: SecureBoot bypass and firmware replacement possible

Recent findings have identified two vulnerabilities in various UEFI BIOS versions from multiple manufacturers, compromising the SecureBoot mechanism. These vulnerabilities allow attackers to bypass SecureBoot protections and replace firmware, particularly in Insyde BIOSes. The issues stem from unprotected NVRAM variables, specifically the "IhisiParamBuffer," which can be manipulated to execute unsigned UEFI binaries. Affected UEFI applications include "DTBios" and "BiosFlashShell" from DTResearch, with a CVSS score of 8.2. Microsoft has added 14 new hashes to its DBX database to mitigate these risks. Additionally, a vulnerability in the Insyde H2O UEFI firmware app allows attackers to infiltrate digital certificates due to the insecure handling of the "SecureFlashCertData" variable, which is incorrectly treated as trusted memory. This flaw, known as "Hydroph0bia," has a CVSS score of 7.8 and enables unauthorized execution of firmware certified with manipulated certificates. Manufacturers are urged to provide firmware updates to address these vulnerabilities, as inconsistent support for locking UEFI variables raises security concerns.