CVE-2021-34557

MediumCVSS 4.6/10Last modified Jun 17, 2026

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.

Metrics

CVSS 3.1 4.6/10CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-120

Affected software

Vendor	Product	Versions
n/a	n/a	n/a

References

http://www.openwall.com/lists/oss-security/2021/06/11/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/07/06/2Exploit, Mailing List, Third Party Advisory
https://github.com/QubesOS/qubes-issues/issues/6595Issue Tracking, Third Party Advisory
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txtExploit, Third Party Advisory
https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patchPatch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/
https://www.openwall.com/lists/oss-security/2021/06/05/1Exploit, Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/06/11/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/07/06/2Exploit, Mailing List, Third Party Advisory
https://github.com/QubesOS/qubes-issues/issues/6595Issue Tracking, Third Party Advisory
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txtExploit, Third Party Advisory
https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patchPatch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/
https://www.openwall.com/lists/oss-security/2021/06/05/1Exploit, Mailing List, Third Party Advisory

Timeline

Published: Jun 10, 2021
Last modified: Jun 17, 2026
NVD status: Modified

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