CVE-2021-34557: Fedoraproject Fedora

Medium severity, CVSS 4.6. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Fedoraproject Fedora: version 33 only
• Xscreensaver Project Xscreensaver: version 5.45 only

Published 2021-06-10. Last modified 2026-06-17.