GHSA-7452-xqpj-6rpc

moby Access to remapped root allows privilege escalation to real root

Source: GitHub Advisory Database (reviewed) Moderate CVE-2021-21284

Packages

Ecosystem	Package	Affected	Fixed in
Go	github.com/moby/moby	< 19.3.15	19.3.15
Go	github.com/moby/moby	>= 20.10.0-beta1, < 20.10.3	20.10.3

Details

As written in the advisory (Markdown source, shown as plain text).

### 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 [email protected]

References

External links from the advisory. They lead to third-party sites.