moby Access to remapped root allows privilege escalation to real root
### 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 security@docker.com
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2021-21284US | medium6.8 | — | ||
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. W… | ||||
references
External citations — patches, advisories, analysis.
- https://docs.docker.com/engine/release-notes/#20103WEB
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7cWEB
- https://github.com/moby/moby/releases/tag/v19.03.15WEB
- https://github.com/moby/moby/releases/tag/v20.10.3WEB
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpcWEB
- https://nvd.nist.gov/vuln/detail/CVE-2021-21284ADVISORY
- https://security.gentoo.org/glsa/202107-23WEB
- https://security.netapp.com/advisory/ntap-20210226-0005WEB
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