CVE-2020-16120

Aliases:UBUNTU-CVE-2020-16120DEBIAN-CVE-2020-16120
Advisory lineage Upstream: 0 Downstream: 20
Modified
Published: 10 Feb 2021, 19:45
Last modified:16 Sept 2024, 18:49

Vulnerability Summary

Overall Risk (default)
low
20/100
CVSS Score
5.1 MEDIUM
v3.1 (cve.org)
EPSS Score
0.41% LOW
0% probability +0.37%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

10 Feb 2021, 19:45
Published
Vulnerability first disclosed
16 Sept 2024, 18:49
Last Modified
Vulnerability information updated

Description

Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef ("ovl: stack file ops"). This was fixed in kernel version 5.8 by commits 56230d9 ("ovl: verify permissions in ovl_path_open()"), 48bd024 ("ovl: switch to mounter creds in readdir") and 05acefb ("ovl: check permission to open real file"). Additionally, commits 130fdbc ("ovl: pass correct flags for opening real directory") and 292f902 ("ovl: call secutiry hook in ovl_real_ioctl()") in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da ("ovl: do not fail because of O_NOATIMEi") in kernel 5.11.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.1CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
  • v3.1•MEDIUM•Score: 4.4CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
  • v2.0•LOW•Score: 2.1AV:L/AC:L/Au:N/C:P/I:N/A:N

EPSS Trends

Current EPSS score: 0.41%• Percentile: 35%

Techniques & Countermeasures

  • CWE-266•Incorrect Privilege Assignment

    A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor.

Affected Systems

  • canonical•ubuntu_linux

    14.04 | 16.04 | 18.04 | 20.04

  • debian•linux

    < 5.8.7-1 | < 5.8.7-1 | < 5.8.7-1 | < 5.8.7-1

  • ubuntu•linux

    all | < 4.15.0-121.123 | < 5.4.0-51.56

  • ubuntu•linux-aws

    all | < 4.15.0-1086.91 | < 5.4.0-1028.29

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1028.29~18.04.1

  • ubuntu•linux-aws-fips

    < 4.15.0-2030.31 | all | < 5.4.0-1069.73+fips2

  • ubuntu•linux-aws-hwe

    < 4.15.0-1085.90~16.04.1

  • ubuntu•linux-azure

    < 4.15.0-1098.109~14.04.1 | < 4.15.0-1098.109~16.04.1 | all | < 5.4.0-1031.32

  • ubuntu•linux-azure-4.15

    < 4.15.0-1099.110

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1031.32~18.04.1

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all

  • ubuntu•linux-azure-fde-5.15

    < 5.15.0-1114.123~20.04.1

  • ubuntu•linux-azure-fips

    < 4.15.0-2012.14 | all | < 5.4.0-1073.76+fips1

  • ubuntu•linux-bluefield

    all

  • ubuntu•linux-fips

    all | < 4.15.0-1044.50

  • ubuntu•linux-gcp

    < 4.15.0-1086.98~16.04.1 | all | < 5.4.0-1028.29

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1086.98

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1028.29~18.04.1

  • ubuntu•linux-gcp-edge

    all

  • ubuntu•linux-gcp-fips

    all | < 5.4.0-1067.71~20.04.1

  • ubuntu•linux-gke

    all

  • ubuntu•linux-gke-4.15

    < 4.15.0-1072.76

  • ubuntu•linux-gke-5.0

    < 5.0.0-1049.50

  • ubuntu•linux-gke-5.3

    < 5.3.0-1038.40

  • ubuntu•linux-gke-5.4

    < 5.4.0-1027.28~18.04.1

  • ubuntu•linux-gkeop-5.4

    < 5.4.0-1003.3

  • ubuntu•linux-hwe

    < 4.15.0-120.122~16.04.1 | < 5.3.0-68.63

  • ubuntu•linux-hwe-5.4

    < 5.4.0-51.56~18.04.1

  • ubuntu•linux-hwe-edge

    all | all

  • ubuntu•linux-intel-iot-realtime

    all

  • ubuntu•linux-kvm

    all | < 4.15.0-1077.79 | < 5.4.0-1026.27

  • ubuntu•linux-lowlatency-hwe-6.2

    all

  • ubuntu•linux-lts-xenial

    all

  • ubuntu•linux-oem

    < 4.15.0-1099.109

  • ubuntu•linux-oem-5.6

    < 5.6.0-1031.32

  • ubuntu•linux-oem-osp1

    < 5.0.0-1069.75

  • ubuntu•linux-oracle

    < 4.15.0-1056.61~16.04.1 | < 4.15.0-1057.62 | < 5.4.0-1028.29

  • ubuntu•linux-oracle-5.0

    all

  • ubuntu•linux-oracle-5.3

    all

  • ubuntu•linux-oracle-5.4

    < 5.4.0-1028.29~18.04.1

  • ubuntu•linux-raspi

    < 5.4.0-1021.24

  • ubuntu•linux-raspi-5.4

    < 5.4.0-1021.24~18.04.1

  • ubuntu•linux-raspi-realtime

    all

  • ubuntu•linux-raspi2

    < 4.15.0-1073.78 | all

  • ubuntu•linux-raspi2-5.3

    < 5.3.0-1035.37

Showing first 50 affected entries in server-rendered view.

References (18)