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CVE-2021-21284

MEDIUM
Published 2021-02-02T17:55:22
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CVSS Score

V3.1
6.8
/10
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
Base Score Metrics
Exploitability: N/A Impact: N/A

EPSS Score

v2025.03.14
0.000
probability
of exploitation in the wild

There is a 0.0% chance that this vulnerability will be exploited in the wild within the next 30 days.

Updated: 2025-06-25
Exploit Probability
Percentile: 0.046
Higher than 4.6% of all CVEs

Attack Vector Metrics

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED

Impact Metrics

Confidentiality
NONE
Integrity
HIGH
Availability
NONE

Description

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.

Available Exploits

No exploits available for this CVE.

Related News

No news articles found for this CVE.

Affected Products

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

✓ GitHub Reviewed MODERATE

moby Access to remapped root allows privilege escalation to real root

GHSA-7452-xqpj-6rpc

Advisory Details

### Impact 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. ### Patches Versions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user. ### Credits Maintainers would like to thank Alex Chapman for discovering the vulnerability; @awprice, @nathanburrell, @raulgomis, @chris-walz, @erin-jensby, @bassmatt, @mark-adams, @dbaxa for working on it and Zac Ellis for responsibly disclosing it to [email protected]

Affected Packages

Go github.com/moby/moby
ECOSYSTEM: ≥0 <19.3.15
Go github.com/moby/moby
ECOSYSTEM: ≥20.10.0-beta1 <20.10.3

CVSS Scoring

CVSS Score

5.0

CVSS Vector

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Advisory provided by GitHub Security Advisory Database. Published: January 31, 2024, Modified: June 10, 2024

References

Published: 2021-02-02T17:55:22
Last Modified: 2024-08-03T18:09:15.042Z
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