CVE-2021-34557

Publication date 10 June 2021

Last updated 26 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

4.6 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
xscreensaver 25.10 questing
Not affected
25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic Ignored end of life, was needs-triage
22.04 LTS jammy
Needs evaluation
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.10 groovy Ignored end of life
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty Not in release

Severity score breakdown

Parameter Value
Base score 4.6 · Medium
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Other references