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.

References

https://www.openwall.com/lists/oss-security/2021/06/05/1

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/

https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch

https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt

https://github.com/QubesOS/qubes-issues/issues/6595

http://www.openwall.com/lists/oss-security/2021/07/06/2

http://www.openwall.com/lists/oss-security/2021/06/11/1

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3