UBUNTU-CVE-2021-3996

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    UBUNTU-CVE-2021-3996

    Published: 1 Feb 2022Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-3996
    Aliases:
    USN-5279-1

    Summary:

    Details: A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

    References: https://ubuntu.com/security/CVE-2021-3996, https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes, https://www.openwall.com/lists/oss-security/2022/01/24/2, https://ubuntu.com/security/notices/USN-5279-1, https://www.cve.org/CVERecord?id=CVE-2021-3996

    Affected packages

    Package

    Name: util-linux

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

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2.34-0.1ubuntu9.3

    Affected versions

    2.34-0.1ubuntu2
    2.34-0.1ubuntu4
    2.34-0.1ubuntu5
    2.34-0.1ubuntu6
    2.34-0.1ubuntu7
    2.34-0.1ubuntu8
    2.34-0.1ubuntu9
    2.34-0.1ubuntu9.1

    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-2021-3996 | CVE-DB