BlackLotus and the 2026 Secure Boot Certificate Expiry: What It Means and How to Fix It

If you manage Windows devices in any kind of enterprise environment, the Secure Boot certificate expiry is a deadline you really do not want to sleep on. The Microsoft certificates that have been the foundation of UEFI Secure Boot since Windows 8 are reaching the end of their lifetime in 2026, and the clock is ticking. The first wave of expirations begins in June 2026, and if your fleet is not ready by then, devices will start losing the ability to receive boot-level security updates and to trust software signed with new certificates.

The reason this matters is not just calendar housekeeping. The whole reason we are rotating these certificates in the first place is the BlackLotus UEFI bootkit (CVE-2023-24932), a piece of malware that can survive an OS reinstall and even bypass Secure Boot itself. The 2023 certificate set is the long term answer, and you need every Windows device in your environment trusting it before the old certificates roll off.

In this post I want to walk through what BlackLotus actually is, what is happening with the Secure Boot certificates, how the two are connected (but not the same thing), and what you can practically do about it today using Intune, PowerShell, and the great work that several Microsoft MVPs have already shared with the community.

A Quick Refresher on BlackLotus

BlackLotus is a UEFI bootkit that exploits CVE-2023-24932, a vulnerability in the Windows boot manager. What makes it particularly nasty is that it loads before Windows does, which means it sits underneath every traditional security control you have in the operating system. Antivirus, EDR, even a clean reinstall of Windows will not necessarily get rid of it, because the malicious code lives in the boot path that Secure Boot is supposed to protect.

Microsoft addressed CVE-2023-24932 with a multi-phase rollout that started back in 2023 and is still in progress today. The fix is not just a patch you install. It involves updating the bootloader, revoking the trust of the vulnerable boot manager, and ultimately replacing the certificates that Secure Boot uses to decide what is allowed to run. That last part is the piece we are dealing with right now.

The Secure Boot Certificate Expiry: What Is Actually Going Away in 2026

There are three Microsoft certificates from 2011 that are baked into firmware on basically every Windows device shipped in the last decade. Here is the short version of what is going away and when:

  • Microsoft Corporation KEK CA 2011 – the Key Enrollment Key authority. Expires June 2026.
  • Microsoft Corporation UEFI CA 2011 – signs third party UEFI components and option ROMs. Expires June 2026.
  • Microsoft Windows Production PCA 2011 – signs the Windows boot manager itself. Expires October 2026.

The replacements are the 2023 certificate set: Microsoft Corporation KEK CA 2023, Microsoft UEFI CA 2023, and Windows UEFI CA 2023. These are the certificates Microsoft is using going forward to sign boot components, and they are also the ones that carry the BlackLotus mitigations.

How BlackLotus and the Certificate Expiry Are Connected, but Not the Same Thing

This is the part I see people mixing up the most, so it is worth being precise. BlackLotus and the certificate expiry are two different problems that share a single solution.

  • BlackLotus (CVE-2023-24932) is a security vulnerability. It exists because the old boot manager can be tricked into running malicious code. The fix is to revoke trust in the vulnerable boot manager and replace it with a new one signed by a new certificate.
  • The 2026 certificate expiry is a lifecycle event. The 2011 certificates were always going to expire eventually. June 2026 is simply when their validity runs out.

Where they meet is the 2023 certificate set. Microsoft is using this rotation as the opportunity to also roll out the BlackLotus mitigations at the same time. So when you update a device to trust the 2023 certificates, you are doing two things in one go: you are getting it ready for life after the 2011 certificates expire, and you are closing the BlackLotus attack path.

If you do nothing, the consequences are not the same on both sides either. A device that never gets the 2023 certificates will still boot after June 2026. It just will not be able to install future Secure Boot updates, will not trust new third party UEFI components, and will remain exposed to BlackLotus style attacks. That is not a place you want to be.

How to Fix It

The good news is that the actual remediation is mostly registry plumbing. Microsoft ships the certificate update logic inside the cumulative update, and you opt a device in to receiving the new certificates by setting a value under HKLM\SYSTEM\CurrentControlSet\Control\Secureboot. Specifically, the AvailableUpdates DWORD controls which steps are applied. The current recommended value is 0x5944, which performs the full sequence: it adds the 2023 KEK to KEK, adds the 2023 DB entries, updates the boot manager, and updates DBX. After the registry value is set, the Microsoft\Windows\PI\Secure-Boot-Update scheduled task is what actually does the work, usually across one or more reboots.

At a high level the process for any device looks like this:

  1. Make sure the device is fully patched. Anything earlier than the July 2024 cumulative update is not going to do you any favors.
  2. Confirm that diagnostic data is set to at least Required, because the certificate update flow uses it.
  3. Set AvailableUpdates to 0x5944 under the Secureboot key.
  4. Trigger the Secure-Boot-Update scheduled task (or wait for it to run on schedule).
  5. Reboot. Sometimes more than once. Verify by checking the UEFICA2023Status registry value, which should eventually read Updated.
  6. Validate by querying the actual Secure Boot databases with PowerShell to confirm the 2023 certificates are present.

The cleanest way to do this at scale is with Intune Remediations. You build a detection script that reports back whether a device already has the 2023 certificates installed, and a remediation script that sets the registry values and kicks off the scheduled task. That gives you a single dashboard view of your whole fleet and lets you target the long tail of devices that need a nudge.

Things That Will Trip You Up

  • OEM firmware. Some older devices will need a UEFI/BIOS update from the manufacturer before they can accept the 2023 certificates. If you have a fleet that is more than four or five years old, plan on doing a firmware audit as part of this project.
  • Diagnostic data. If telemetry is set to Off (Security on Enterprise), the certificate update flow will not run. You need at least Required.
  • Dual boot and custom signed bootloaders. If you are running anything that depends on the 2011 UEFI CA (some Linux distributions, some hardware vendors’ utilities), test before you push the update broadly.
  • Virtual machines. Hyper-V Generation 2 VMs and Azure VMs are also affected. Do not forget the server side of the house.
  • Monitor first, remediate second. Microsoft’s recommended approach is to start with a monitor-only Intune Remediation that just reports status, so you understand the scope of the problem before you start changing anything.

Reference Articles From the Community

I am far from the first person to write about this, and several Microsoft MVPs have already done excellent deep dives that are well worth your time. If you are about to start this project, read these first:

GitHub Scripts You Can Use Today

If you would rather start from working code than write your own from scratch, several community members have published their detection and remediation scripts on GitHub. Always read through any script before deploying it in your environment, but these are good starting points:

Conclusion

The 2026 Secure Boot certificate rotation is one of those rare projects that touches every Windows device in your environment, including the ones nobody has thought about in years. It is also one of those projects that is going to be infinitely easier if you start now than if you wait until May 2026 and try to do it under pressure. The combination of Intune Remediations, the registry-based opt-in flow, and the great scripts already shared by the community means there is no real reason to put it off.

Start with monitoring so you know what you are dealing with, fix any firmware and telemetry prerequisites, and then roll out the remediation in waves. Closing the door on BlackLotus is a nice bonus on top of staying ahead of the certificate expiry, and your future self (and your security team) will thank you.

Unified Extensible Firmware Interface (UEFI)

Unified Extensible Firmware Interface

For many years BIOS has been the industry standard for booting a PC. BIOS has served us well, but it is time to replace it with something better. UEFI is the replacement for BIOS, so it is important to understand the differences between BIOS and UEFI. In this section, you learn the major differences between the two and how they affect operating system deployment.

Introduction to UEFI

BIOS has been in use for approximately 30 years. Even though it clearly has proven to work, it has some limitations, including:

  • 16-bit code
  • 1 MB address space
  • Poor performance on ROM initialization
  • MBR maximum bootable disk size of 2.2 TB

As the replacement to BIOS, UEFI has many features that Windows can and will use.

With UEFI, you can benefit from:

  • Support for large disks. UEFI requires a GUID Partition Table (GPT) based disk, which means a limitation of roughly 16.8 million TB in disk size and more than 100 primary disks.
  • Faster boot time. UEFI does not use INT 13, and that improves boot time, especially when it comes to resuming from hibernate.
  • Multicast deployment. UEFI firmware can use multicast directly when it boots up. In WDS, MDT, and Configuration Manager scenarios, you need to first boot up a normal Windows PE in unicast and then switch into multicast. With UEFI, you can run multicast from the start.
  • Compatibility with earlier BIOS. Most of the UEFI implementations include a compatibility support module (CSM) that emulates BIOS.
  • CPU-independent architecture. Even if BIOS can run both 32- and 64-bit versions of firmware, all firmware device drivers on BIOS systems must also be 16-bit, and this affects performance. One of the reasons is the limitation in addressable memory, which is only 64 KB with BIOS.
  • CPU-independent drivers. On BIOS systems, PCI add-on cards must include a ROM that contains a separate driver for all supported CPU architectures. That is not needed for UEFI because UEFI has the ability to use EFI Byte Code (EBC) images, which allow for a processor-independent device driver environment.
  • Flexible pre-operating system environment. UEFI can perform many functions for you. You just need an UEFI application, and you can perform diagnostics and automatic repairs, and call home to report errors.
  • Secure boot. Windows 8 and later can use the UEFI firmware validation process, called secure boot, which is defined in UEFI 2.3.1. Using this process, you can ensure that UEFI launches only a verified operating system loader and that malware cannot switch the boot loader.

Versions

UEFI Version 2.3.1B is the version required for Windows 8 and later logo compliance. Later versions have been released to address issues; a small number of machines may need to upgrade their firmware to fully support the UEFI implementation in Windows 8 and later.

Hardware support for UEFI

In regard to UEFI, hardware is divided into four device classes:

  • Class 0 devices. This is the UEFI definition for a BIOS, or non-UEFI, device.
  • Class 1 devices. These devices behave like a standard BIOS machine, but they run EFI internally. They should be treated as normal BIOS-based machines. Class 1 devices use a CSM to emulate BIOS. These older devices are no longer manufactured.
  • Class 2 devices. These devices have the capability to behave as a BIOS- or a UEFI-based machine, and the boot process or the configuration in the firmware/BIOS determines the mode. Class 2 devices use a CSM to emulate BIOS. These are the most common type of devices currently available.
  • Class 3 devices. These are UEFI-only devices, which means you must run an operating system that supports only UEFI. Those operating systems include Windows 8, Windows 8.1, Windows Server 2012, and Windows Server 2012 R2. Windows 7 is not supported on these class 3 devices. Class 3 devices do not have a CSM to emulate BIOS.

Windows support for UEFI

Microsoft started with support for EFI 1.10 on servers and then added support for UEFI on both clients and servers.

With UEFI 2.3.1, there are both x86 and x64 versions of UEFI. Windows 10 supports both. However, UEFI does not support cross-platform boot. This means that a computer that has UEFI x64 can run only a 64-bit operating system, and a computer that has UEFI x86 can run only a 32-bit operating system.

How UEFI is changing operating system deployment

There are many things that affect operating system deployment as soon as you run on UEFI/EFI-based hardware. Here are considerations to keep in mind when working with UEFI devices:

  • Switching from BIOS to UEFI in the hardware is easy, but you also need to reinstall the operating system because you need to switch from MBR/NTFS to GPT/FAT32 and NTFS.
  • When you deploy to a Class 2 device, make sure the boot option you select matches the setting you want to have. It is common for old machines to have several boot options for BIOS but only a few for UEFI, or vice versa.
  • When deploying from media, remember the media has to be FAT32 for UEFI, and FAT32 has a file-size limitation of 4GB.
  • UEFI does not support cross-platform booting; therefore, you need to have the correct boot media (32- or 64-bit).