Minimal risk (from what information offered), you are better off to isolate & disconnect then apply this patch if you really think this is a high-level threat. The irony is anyone without "Secure Boot" is no less at risk & doesn't have the issue. I am in legacy mode with a UEFI BIOS, this patch isn't that critical.
Stability trumps here. There is no remote access or non user intervention scope that they reported to the issue.
Or perhaps give them the benefit of doubt & perhaps it is "so sever" they couldn't publish a legible definition of what this patch is supposed to protect against.
Like the "Spectre" scope, that patch caused way more harm to stability than it resolved. Albeit thanks to A Google engineer for reportedly releasing the details before a patch was properly tested. How long did it take & how many W10 OS builds to sort that out.