Permissions, Privileges, and Access Controls in Docker - CVE-2021-21284

Vulnerability identifier: #VU50273

CSH Severity: Medium

CVSS v4: 8.6 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-21284

CWE-ID: CWE-264

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions when using the --userns-remap option. A remote authenticated attacker on the local network can send a specially crafted request and gain elevated privileges as root on the system.

Docker
Arch Linux
Gentoo Linux
Amazon Linux AMI
SUSE CaaS Platform
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE MicroOS
SUSE Enterprise Storage
SUSE Linux Enterprise Module for Containers
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Server
openEuler
IBM Cloud Automation Manager
docker.io (Debian package)
docker (Alpine package)
runc
runc-debuginfo
containerd
docker-engine
docker
docker-debuginfo
Dell EMC VxRail Appliance
Storage Ceph

Install updates from vendor's website.

Docker - addressed in versions 19.03.15, 20.10.3
docker.io (Debian package) - update to 18.09.1+dfsg1-7.1+deb10u3
docker (Alpine package) - update to 20.10.3-r0
runc - update to 1.0.0~rc93-16.8.1
runc-debuginfo - update to 1.0.0~rc93-16.8.1
containerd - addressed in versions 1.4.4-5.32.1, 1.4.4-16.38.1
Dell EMC VxRail Appliance - update to 7.0.203
Storage Ceph - update to 7.1
docker-engine - update to 18.09.0-202
docker - update to 20.10.6_ce-98.66.1
docker-debuginfo - update to 20.10.6_ce-98.66.1

• 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

• Multiple vulnerabilities in Docker
• Arch Linux update for docker
• Permissions, Privileges, and Access Controls in docker (Alpine package)
• Debian update for docker.io
• Gentoo update for Docker
• Amazon Linux AMI update for docker
• SUSE update for containerd, docker, runc
• Multiple vulnerabilities in Dell EMC VxRail Appliance
• SUSE update for containerd, docker, runc
• Multiple vulnerabilities in IBM Cloud Automation Manager
• openEuler update for docker
• Multiple vulnerabilities in IBM Storage Ceph