CVE-2021-21284
moby Access to remapped root allows privilege escalation to real root
6.8
MEDIUM
CVSS 3.1
EPSS 0.02%
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.
How to fix CVE-2021-21284
To remediate CVE-2021-21284, upgrade the affected package to a fixed version below.
- —upgrade to 20.10.3+dfsg1-1 or later
- —upgrade to 19.3.15 or later
Is CVE-2021-21284 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 20.10.3+dfsg1-1
- from 0, < 19.3.15
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.8 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N |