Race Condition Affecting github.com/opencontainers/runc/libcontainer package, versions <1.0.0-rc10

  • Attack Complexity


  • Confidentiality


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  • snyk-id


  • published

    2 Jan 2020

  • disclosed

    24 Dec 2019

  • credit


How to fix?

Upgrade github.com/opencontainers/runc/libcontainer to version 1.0.0-rc10 or higher.


github.com/opencontainers/runc/libcontainer is a package for a modern container runtime.

Affected versions of this package are vulnerable to Race Condition an attacker who controls the container image for two containers that share a volume can race volume mounts during container initialization, by adding a symlink to the rootfs that points to a directory on the volume. The second container won't be able to see the actual mount, but it can race it by modifying the mount point on the volume.

This can be exploited for a full container breakout by racing readonly/mask mounts, allowing writes to dangerous paths like /proc/sys/kernel/core_pattern.