CVE-2021-21284
What it is
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.
At a glance
- Exploitability
- Can be exploited from the same network segment with a low-privilege account. High risk of data tampering.
- Exploit odds
- 1.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 1.1% in the next 30 days (EPSS).
- Severity: 6.8 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 1.1% · EPSS, next 30 days
- Weakness
- CWE-22 · Path traversal
- Record status
- Modified
Affected
- Docker < 19.03.15
- Docker < 20.10.3
- Debian Linux 10.0
- Netapp e-series Santricity Os Controller ≤ 11.60.3
Attack profile CVSS 3.1 · 6.8
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-21284.md and follow it. Check whether this project is affected by CVE-2021-21284. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
- https://security.gentoo.org/glsa/202107-23
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
References
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
- https://security.gentoo.org/glsa/202107-23
- https://security.netapp.com/advisory/ntap-20210226-0005/
- https://www.debian.org/security/2021/dsa-4865
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
- https://security.gentoo.org/glsa/202107-23
- https://security.netapp.com/advisory/ntap-20210226-0005/
- https://www.debian.org/security/2021/dsa-4865