CVE-2021-34557

Name	CVE-2021-34557
Description	XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authentication mechanism by crashing XScreenSaver. The attacker must physically disconnect many video outputs.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
Debian Bugs	989508

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
xscreensaver (PTS)	buster	5.42+dfsg1-1	vulnerable
	bullseye	5.45+dfsg1-2	fixed
	bookworm, sid	6.02+dfsg1-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
xscreensaver	source	(unstable)	5.45+dfsg1-2			989508

Notes

[buster] - xscreensaver <no-dsa> (Minor issue)
[stretch] - xscreensaver <postponed> (Minor issue, fix along with next dla)
https://www.openwall.com/lists/oss-security/2021/06/05/1
https://www.openwall.com/lists/oss-security/2021/06/05/2
https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch