UBUNTU-CVE-2021-21284

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Source
https://ubuntu.com/security/CVE-2021-21284
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-21284.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2021-21284
Upstream
Related
Published
2021-02-02T18:15:00Z
Modified
2025-09-08T16:46:57Z
Severity
  • 6.8 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N CVSS Calculator
  • 6.8 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

In Docker before versions 9.03.15, 20.10.3 there is a vulnerability involving the --userns-remap option in which access to remapped root allows privilege escalation to real root. When using "--userns-remap", if the root user in the remapped namespace has access to the host filesystem they can modify files under "/var/lib/docker/<remapping>" that cause writing files with extended privileges. Versions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user.

References

Affected packages

Ubuntu:Pro:16.04:LTS / docker.io

Package

Name
docker.io
Purl
pkg:deb/ubuntu/docker.io@18.09.7-0ubuntu1~16.04.9+esm2?arch=source&distro=esm-infra/xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.6.2~dfsg1-1ubuntu4
1.10.2-0ubuntu3
1.10.2-0ubuntu4
1.10.3-0ubuntu1
1.10.3-0ubuntu4
1.10.3-0ubuntu5
1.10.3-0ubuntu6
1.11.2-0ubuntu5~16.04
1.12.1-0ubuntu13~16.04.1
1.12.3-0ubuntu4~16.04.2
1.12.6-0ubuntu1~16.04.1
1.13.1-0ubuntu1~16.04.2

17.*

17.03.2-0ubuntu2~16.04.1

18.*

18.06.1-0ubuntu1~16.04.2
18.06.1-0ubuntu1.2~16.04.1
18.09.2-0ubuntu1~16.04.1
18.09.5-0ubuntu1~16.04.2
18.09.7-0ubuntu1~16.04.1
18.09.7-0ubuntu1~16.04.4
18.09.7-0ubuntu1~16.04.5
18.09.7-0ubuntu1~16.04.6
18.09.7-0ubuntu1~16.04.7
18.09.7-0ubuntu1~16.04.9+esm1
18.09.7-0ubuntu1~16.04.9+esm2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "18.09.7-0ubuntu1~16.04.9+esm2",
            "binary_name": "docker.io"
        },
        {
            "binary_version": "18.09.7-0ubuntu1~16.04.9+esm2",
            "binary_name": "golang-docker-dev"
        },
        {
            "binary_version": "18.09.7-0ubuntu1~16.04.9+esm2",
            "binary_name": "golang-github-docker-docker-dev"
        },
        {
            "binary_version": "18.09.7-0ubuntu1~16.04.9+esm2",
            "binary_name": "vim-syntax-docker"
        }
    ]
}

Ubuntu:18.04:LTS / docker.io

Package

Name
docker.io
Purl
pkg:deb/ubuntu/docker.io@20.10.7-0ubuntu1~18.04.1?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
20.10.7-0ubuntu1~18.04.1

Affected versions

1.*

1.13.1-0ubuntu6

17.*

17.03.2-0ubuntu1
17.03.2-0ubuntu3
17.03.2-0ubuntu5
17.12.1-0ubuntu1

18.*

18.06.1-0ubuntu1~18.04.1
18.06.1-0ubuntu1.2~18.04.1
18.09.2-0ubuntu1~18.04.1
18.09.5-0ubuntu1~18.04.2
18.09.7-0ubuntu1~18.04.1
18.09.7-0ubuntu1~18.04.3
18.09.7-0ubuntu1~18.04.4

19.*

19.03.6-0ubuntu1~18.04.1
19.03.6-0ubuntu1~18.04.2
19.03.6-0ubuntu1~18.04.3

20.*

20.10.2-0ubuntu1~18.04.2
20.10.2-0ubuntu1~18.04.3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_version": "20.10.7-0ubuntu1~18.04.1",
            "binary_name": "docker.io"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~18.04.1",
            "binary_name": "golang-docker-dev"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~18.04.1",
            "binary_name": "golang-github-docker-docker-dev"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~18.04.1",
            "binary_name": "vim-syntax-docker"
        }
    ]
}

Ubuntu:20.04:LTS / docker.io

Package

Name
docker.io
Purl
pkg:deb/ubuntu/docker.io@20.10.7-0ubuntu1~20.04.1?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
20.10.7-0ubuntu1~20.04.1

Affected versions

19.*

19.03.2-0ubuntu1
19.03.6-0ubuntu1
19.03.8-0ubuntu1
19.03.8-0ubuntu1.20.04
19.03.8-0ubuntu1.20.04.1
19.03.8-0ubuntu1.20.04.2

20.*

20.10.2-0ubuntu1~20.04.2
20.10.2-0ubuntu1~20.04.3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_version": "20.10.7-0ubuntu1~20.04.1",
            "binary_name": "docker.io"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~20.04.1",
            "binary_name": "golang-docker-dev"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~20.04.1",
            "binary_name": "golang-github-docker-docker-dev"
        },
        {
            "binary_version": "20.10.7-0ubuntu1~20.04.1",
            "binary_name": "vim-syntax-docker"
        }
    ]
}