| 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, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/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) | jessie, jessie (lts) | 5.30-1+deb8u2 | vulnerable |
| stretch | 5.36-1 | vulnerable |
| buster | 5.42+dfsg1-1 | vulnerable |
| bullseye | 5.45+dfsg1-2 | fixed |
| bookworm | 6.06+dfsg1-3 | fixed |
| sid, trixie | 6.08+dfsg1-1 | fixed |
The information below is based on the following data on fixed versions.
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