Security News > 2022 > August > Windows KB5012170 Secure Boot DBX update may fail with 0x800f0922 error
Microsoft is warning that users may see a 0x800f0922 error when trying to install Windows KB5012170 Secure Boot security update on currently supported operating systems for consumers and the enterprise-class Server version.
Error 0x800f0922 is related strictly to KB5012170, a security update for the Secure Boot DBX, a repository that holds revoked signatures for Unified Extensible Firmware Interface bootloaders.
A UEFI bootloader runs immediately after turning on the system and is responsible for launching the UEFI environment with the Secure Boot feature that allows only trusted code to be executed when starting the Windows booting process.
Microsoft has addressed the issue by adding the signatures of the bootloaders above to the Secure Boot DBX so that vulnerable UEFI modules can no longer load. On systems that start with one of the three now revoked bootloaders, Microsoft says that the KB5012170 update will generate error 0x800f0922 since a bootloader is essential for Windows to launch with Secure Boot.
Researchers at Eclypsium recommend organizations check if the bootloaders on their systems are vulnerable before trying to update the DBX revocation list.
The researchers warn that updating the DBX revocation list on systems with vulnerable bootloaders, where this is possible, will lead to device boot failure.