UBUNTU-CVE-2021-3996

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Source
https://ubuntu.com/security/CVE-2021-3996
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3996.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2021-3996
Upstream
Downstream
Related
Published
2022-02-01T00:00:00Z
Modified
2025-09-08T16:46:50Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
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

Affected packages

Ubuntu:20.04:LTS / util-linux

Package

Name
util-linux
Purl
pkg:deb/ubuntu/util-linux@2.34-0.1ubuntu9.3?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.34-0.1ubuntu9.3

Affected versions

2.*

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.34-0.1ubuntu9.3",
            "binary_name": "bsdutils"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "fdisk"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libblkid-dev"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libblkid1"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libfdisk-dev"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libfdisk1"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libmount-dev"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libmount1"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libsmartcols-dev"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libsmartcols1"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "libuuid1"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "mount"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "rfkill"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "util-linux"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "util-linux-locales"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "uuid-dev"
        },
        {
            "binary_version": "2.34-0.1ubuntu9.3",
            "binary_name": "uuid-runtime"
        }
    ],
    "availability": "No subscription required"
}

Ubuntu:22.04:LTS / util-linux

Package

Name
util-linux
Purl
pkg:deb/ubuntu/util-linux@2.37.2-4ubuntu2?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.37.2-4ubuntu2

Affected versions

2.*

2.36.1-8ubuntu1
2.37.2-4ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "bsdextrautils"
        },
        {
            "binary_version": "1:2.37.2-4ubuntu2",
            "binary_name": "bsdutils"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "eject"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "fdisk"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libblkid-dev"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libblkid1"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libfdisk-dev"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libfdisk1"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libmount-dev"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libmount1"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libsmartcols-dev"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libsmartcols1"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "libuuid1"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "mount"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "rfkill"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "util-linux"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "util-linux-locales"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "uuid-dev"
        },
        {
            "binary_version": "2.37.2-4ubuntu2",
            "binary_name": "uuid-runtime"
        }
    ],
    "availability": "No subscription required"
}