CVE-2021-47255

Name	CVE-2021-47255
Description	In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	buster	4.19.249-2	fixed
	buster (security)	4.19.316-1	fixed
	bullseye	5.10.209-2	fixed
	bullseye (security)	5.10.218-1	fixed
	bookworm	6.1.76-1	fixed
	bookworm (security)	6.1.90-1	fixed
	trixie	6.8.12-1	fixed
	sid	6.9.7-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	buster	(not affected)
linux	source	(unstable)	5.10.46-1

[buster] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/218bf772bddd221489c38dde6ef8e917131161f6 (5.13-rc7)