Arch Linux Security Advisory ASA-202102-12
=========================================
Severity: Medium
Date    : 2021-02-06
CVE-ID  : CVE-2021-21284 CVE-2021-21285
Package : docker
Type    : multiple issues
Remote  : No
Link    : https://security.archlinux.org/AVG-1528

Summary
======
The package docker before version 1:20.10.3-1 is vulnerable to multiple
issues including denial of service and privilege escalation.

Resolution
=========
Upgrade to 1:20.10.3-1.

# pacman -Syu "docker>=1:20.10.3-1"

The problems have been fixed upstream in version 20.10.3.

Workaround
=========
None.

Description
==========
- CVE-2021-21284 (privilege escalation)

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/"
that cause writing files with extended privileges. Versions 20.10.3 and
19.03.15 contain patches that prevent privilege escalation from
remapped user.

- CVE-2021-21285 (denial of service)

In Docker before versions 9.03.15, 20.10.3 there is a vulnerability in
which pulling an intentionally malformed Docker image manifest crashes
the dockerd daemon. Versions 20.10.3 and 19.03.15 contain patches that
prevent the daemon from crashing.

Impact
=====
An attacker could crash the dockerd daemon via a crafted image. An
attacker with root access inside a docker container can escape the
container.

References
=========
https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
https://github.com/moby/moby/commit/edb62a3ace8c4303822a391b38231e577f8c2ee8
https://github.com/moby/moby/commit/bfedd2725971303efb7a2fe5d6990317b381622f
https://github.com/moby/moby/commit/e908cc39018c015084ffbffbc5703ccba5c2fbb7
https://github.com/moby/moby/security/advisories/GHSA-6fj5-m822-rqx8
https://github.com/moby/moby/commit/a7d4af84bd2f189b921c3ec60796aa825e3a0f2a
https://security.archlinux.org/CVE-2021-21284
https://security.archlinux.org/CVE-2021-21285