CVE-2020-27749

Name	CVE-2020-27749
Description	A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-4867-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
grub2 (PTS)	jessie, jessie (lts)	2.02~beta2-22+deb8u2	vulnerable
	stretch (lts), stretch	2.02~beta3-5+deb9u3	vulnerable
	buster (security), buster, buster (lts)	2.06-3~deb10u4	fixed
	bullseye (security), bullseye	2.06-3~deb11u6	fixed
	bookworm (security), bookworm	2.06-13+deb12u1	fixed
	sid, trixie	2.12-5	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
grub2	source	buster	2.02+dfsg1-20+deb10u4		DSA-4867-1
grub2	source	(unstable)	2.04-16

[stretch] - grub2 <ignored> (No SecureBoot support in stretch)
[jessie] - grub2 <ignored> (No SecureBoot support in jessie)