“Something has gone seriously wrong,” dual

The reports indicate that multiple distributions, including Debian, Ubuntu, Linux Mint, Zorin OS, and Puppy Linux, are all affected. Microsoft has yet to acknowledge the error publicly, explain how it wasn’t detected during testing, or provide technical guidance to those affected. Company representatives didn’t respond to an email seeking answers.

[Update: Roughly 17 hours after this post went live, Microsoft supplied the following statement, which also doesn’t answer those questions: “This update is not applied when a Linux boot option is detected. We are aware that some secondary boot scenarios are causing issues for some customers, including when using outdated Linux loaders with vulnerable code. We are working with our Linux partners to investigate and address.”]

Microsoft’s bulletin for CVE-20220-2601 explained that the update would install an SBAT—a Linux mechanism for revoking various components in the boot path—but only on devices configured to run only Windows. That way, Secure Boot on Windows devices would no longer be vulnerable to attacks that loaded a GRUB package that exploited the vulnerability. Microsoft assured users their dual-boot systems wouldn’t be affected, although it did warn that devices running older versions of Linux could experience problems.

“The SBAT value is not applied to dual-boot systems that boot both Windows and Linux and should not affect these systems,” the bulletin read. “You might find that older Linux distribution ISOs will not boot. If this occurs, work with your Linux vendor to get an update.”

In fact, the update has been applied to devices that boot both Windows and Linux. That not only includes dual-boot devices but also Windows devices that can boot Linux from an ISO image, a USB drive, or optical media. What’s more, many of the affected systems run recently released Linux versions, including Ubuntu 24.04 and Debian 12.6.0.