CVE-2020-27837

Name	CVE-2020-27837
Description	A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit.
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
gdm3 (PTS)	buster	3.30.2-3	vulnerable
	bullseye	3.38.2.1-1	fixed
	bookworm	43.0-3	fixed
	trixie	45.0.1-3	fixed
	sid	46.0-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
gdm3	source	(unstable)	3.38.2.1-1

Notes

[buster] - gdm3 <no-dsa> (Minor issue)
[stretch] - gdm3 <no-dsa> (Minor issue)
https://gitlab.gnome.org/GNOME/gdm/-/issues/660
https://gitlab.gnome.org/GNOME/gdm/-/commit/dcdbaaa04012541ad2813cf83559d91d52f208b9 (master)
https://gitlab.gnome.org/GNOME/gdm/-/commit/9b6d9b24a5f69674447c7bc9aacfab0988b914bd (3.38.2.1)