CVE-2019-19921 opencontainers runc contains procfs race condition with a shared volume mount

High 7.0 Published 12 Feb 2020 Updated 5 Aug 2024

An attacker with container spawn privileges can escalate privileges via custom volume mounts in runc, bypassing isolation controls.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2019-19921?

CVE-2019-19921 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 12 Feb 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

runc through 1.0.0-rc9 has Incorrect Access Control leading to Escalation of Privileges, related to libcontainer/rootfs_linux.go. To exploit this, an attacker must be able to spawn two containers with custom volume-mount configurations, and be able to run custom images. (This vulnerability does not affect Docker due to an implementation detail that happens to block the attack.)

Weakness: CWE-706

Which versions are affected by CVE-2019-19921?

3 open source packages ship an affected version, including github.com/opencontainers/runc. It affects 5 products.

Package	Affected	Fixed in
`github.com/opencontainers/runc` Go	All versions	`1.0.0-rc9.0.20200122160610-2fc03cc11c77`
`github.com/opencontainers/runc` Go	All versions	`1.0.0-rc9.0.20200122160610-2fc03cc11c77`
`github.com/opencontainers/runc` Go	All versions	`1.0.0-rc9.0.20200122160610-2fc03cc11c77`

Linux distribution packages (14)

`runc` Red Hat:openshift:4.1::el8	All versions	`0:1.0.0-63.rc8.rhaos4.1.git3cbe540.el8_0`
`runc-debuginfo` Red Hat:openshift:4.1::el8	All versions	`0:1.0.0-63.rc8.rhaos4.1.git3cbe540.el8_0`
`runc-debugsource` Red Hat:openshift:4.1::el8	All versions	`0:1.0.0-63.rc8.rhaos4.1.git3cbe540.el8_0`
`runc` Red Hat:openshift:4.2::el8	All versions	`0:1.0.0-63.rc10.rhaos4.2.gitdc9208a.el8`
`runc-debuginfo` Red Hat:openshift:4.2::el8	All versions	`0:1.0.0-63.rc10.rhaos4.2.gitdc9208a.el8`
`runc-debugsource` Red Hat:openshift:4.2::el8	All versions	`0:1.0.0-63.rc10.rhaos4.2.gitdc9208a.el8`
`runc` Red Hat:openshift:4.3::el7	All versions	`0:1.0.0-66.rc10.rhaos4.3.el7_8`
`runc-debuginfo` Red Hat:openshift:4.3::el7	All versions	`0:1.0.0-66.rc10.rhaos4.3.el7_8`
`runc` Red Hat:rhel_extras_other:7	All versions	`0:1.0.0-66.rc8.el7_7`
`runc-debuginfo` Red Hat:rhel_extras_other:7	All versions	`0:1.0.0-66.rc8.el7_7`
`docker-runc` SUSE:Linux Enterprise Module for Containers 12	All versions	`1.0.0rc8+gitr3917_3e425f80a8c9-1.40.1`
`docker-runc` SUSE:Linux Enterprise Module for Containers 15 SP1	All versions	`1.0.0rc8+gitr3917_3e425f80a8c9-6.32.1`
`runc` SUSE:Linux Enterprise Module for Containers 15 SP1	All versions	`1.0.0~rc10-1.9.1`
`docker-runc` openSUSE:Leap 15.1	All versions	`1.0.0rc8+gitr3917_3e425f80a8c9-lp151.3.15.1`

Products include Canonical Ubuntu Linux, Debian Debian Linux, Linuxfoundation Runc, Opensuse Leap, Redhat Openshift Container Platform.

How do I fix CVE-2019-19921?

Upgrade github.com/opencontainers/runc to 1.0.0-rc9.0.20200122160610-2fc03cc11c77 or later.

Is CVE-2019-19921 being exploited?

There is no known exploitation of CVE-2019-19921 in the wild and no public exploit code.

All Canonical Ubuntu Linux vulnerabilities

Sources

Also known as CLEANSTART-2025-NR50910, CLEANSTART-2026-UZ87660, DEBIAN-CVE-2019-19921, GHSA-fh74-hm69-rqjw, GO-2021-0087, MGASA-2020-0103 and 9 more.