DEBIAN-CVE-2021-21284

Advisory lineage Upstream: 1 Downstream: 1
Upstream
CVE-2021-21284
Downstream
DSA-4865-1
Published: 02 Feb 2021, 18:15
Last modified:28 Apr 2026, 20:22

Vulnerability Summary

Overall Risk (default)
medium
27/100
CVSS Score
6.8 MEDIUM
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

02 Feb 2021, 18:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:22
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 6.8CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Affected Systems

  • debian•docker.io

    < 20.10.3+dfsg1-1 | < 20.10.3+dfsg1-1 | < 20.10.3+dfsg1-1 | < 20.10.3+dfsg1-1

References (1)