{"id":"CVE-2021-21284","aliases":["GHSA-7452-xqpj-6rpc"],"url":"https://o3.security/vulnerability/CVE-2021-21284","summary":"moby Access to remapped root allows privilege escalation to real root","details":"### Impact\n\nWhen 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.\n\n### Patches\n\nVersions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user.\n\n### Credits\n\nMaintainers 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","published":"2021-02-02T18:15:11.827Z","modified":"2026-08-27T03:49:17.677386280Z","cvss":{"score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/moby/moby","fixedVersion":"19.3.15"},{"ecosystem":"Go","name":"github.com/moby/moby","fixedVersion":"20.10.3"}],"fix":{"url":"https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c","label":"moby/moby@64bd448"},"references":[{"type":"ADVISORY","url":"https://docs.docker.com/engine/release-notes/#20103"},{"type":"ADVISORY","url":"https://github.com/moby/moby/releases/tag/v19.03.15"},{"type":"ADVISORY","url":"https://github.com/moby/moby/releases/tag/v20.10.3"},{"type":"ADVISORY","url":"https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20210226-0005/"},{"type":"ADVISORY","url":"https://www.debian.org/security/2021/dsa-4865"},{"type":"FIX","url":"https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c"},{"type":"FIX","url":"https://security.gentoo.org/glsa/202107-23"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21284"},{"type":"WEB","url":"https://security.netapp.com/advisory/ntap-20210226-0005"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T03:49:17.677386280Z"}}