The KB (replacing, though not technically superseding KB4535680) is related to Microsoft Security Response Center (MSRC)‘s Security Advisory ADV200011, which was released on July 29, 2020, but last updated on Aug(together with the KB release). Azure Stack Data Box (ASDB = Azure Data Box), version 1809.Azure Stack HCI, version 20H2 (the KB mentions version 1809, but I guess the initial version (20H2) is meant, which is based on Windows Server 2019 (which belongs to Windows Server version 1809)).Most (or even all?) vendor shims are already available with newer versions, which use the newest GRUB (2.06), which is not vulnerable anymore. Microsoft Update Catalog (for a direct download).The update is available through the following update channels: With KB5012170 Secure Boot’s dbx database gets updated in such a way specific vendor shim versions starting vulnerable GRUB versions get blacklisted, so updated systems get protected against the aforementioned vulnerability. The latest servicing stack update (SSU) should be installed first and a reboot is not needed (except twice, when Windows Defender Credential Guard (Virtual Secure Mode) is enabled). The KB, which refers to standalone security updates, is titled KB5012170: Security update for Secure Boot DBX: August 9, 2022. With Patch Tuesday of August 2022 (August 9, 2022) Microsoft has released KB5012170, which finally addresses the so-called BootHole vulnerability discovered in 2020 in the GRand Unified Bootloader (GRUB) bootloader when being used in a Secure Boot context.

See the bottom of this post for more information. UPDATE: this update has introduced some issues. KB5012170 released to combat GRUB2 vulnerability in Secure Boot context (BootHole)

Kb4535680 0x800f0922