UBUNTU-CVE-2021-34557

    Dashboard / Vulnerabilities / UBUNTU-CVE-2021-34557

    UBUNTU-CVE-2021-34557

    Published: 10 Jun 2021Last Modified: 24 Oct 2025
    Upstream:
    CVE-2021-34557

    Summary:

    Details: 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://ubuntu.com/security/CVE-2021-34557, https://www.openwall.com/lists/oss-security/2021/06/05/1, https://www.openwall.com/lists/oss-security/2021/06/05/2, 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.cve.org/CVERecord?id=CVE-2021-34557

    Affected packages

    Package

    Name: xscreensaver

    Purl: pkg:deb/ubuntu/[email protected]?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    5.30-1ubuntu1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2021-34557 | CVE-DB