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`docker cp` allows unexpected chmod of host files in Moby Docker Engine

Low severity GitHub Reviewed Published Oct 4, 2021 in moby/moby • Updated Jul 3, 2024

Package

gomod github.com/docker/docker (Go)

Affected versions

< 20.10.9

Patched versions

20.10.9

Description

Impact

A bug was found in Moby (Docker Engine) where attempting to copy files using docker cp into a specially-crafted container can result in Unix file permission changes for existing files in the host’s filesystem, widening access to others. This bug does not directly allow files to be read, modified, or executed without an additional cooperating process.

Patches

This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers do not need to be restarted.

Workarounds

Ensure you only run trusted containers.

Credits

The Moby project would like to thank Lei Wang and Ruizhi Xiao for responsibly disclosing this issue in accordance with the Moby security policy.

For more information

If you have any questions or comments about this advisory:

References

@thaJeztah thaJeztah published to moby/moby Oct 4, 2021
Published by the National Vulnerability Database Oct 4, 2021
Published to the GitHub Advisory Database Jun 10, 2024
Reviewed Jun 10, 2024
Last updated Jul 3, 2024

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS score

0.047%
(18th percentile)

Weaknesses

CVE ID

CVE-2021-41089

GHSA ID

GHSA-v994-f8vw-g7j4

Source code

Credits

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