CVE-2021-34557 Information

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.

CVSS Vector

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

Reference

https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch https://github.com/QubesOS/qubes-issues/issues/6595 https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt https://www.openwall.com/lists/oss-security/2021/06/05/1 http://www.openwall.com/lists/oss-security/2021/06/11/1 http://www.openwall.com/lists/oss-security/2021/07/06/2 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

4.6