CVE-2020-28049

Name	CVE-2020-28049
Description	An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-2436-1, DSA-4783-1
Debian Bugs	973748

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
sddm (PTS)	buster, buster (security)	0.18.0-1+deb10u1	fixed
	bullseye	0.19.0-3	fixed
	bookworm	0.19.0-5	fixed
	sid, trixie	0.20.0-2	fixed

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

Package	Type	Release	Fixed Version	Origin	Debian Bugs
sddm	source	stretch	0.14.0-4+deb9u2	DLA-2436-1
sddm	source	buster	0.18.0-1+deb10u1	DSA-4783-1
sddm	source	(unstable)	0.19.0-1		973748

Notes

https://www.openwall.com/lists/oss-security/2020/11/04/2
https://github.com/sddm/sddm/commit/be202f533ab98a684c6a007e8d5b4357846bc222
https://bugzilla.suse.com/show_bug.cgi?id=1177201