In the toolkit to start isolated containers runc used in docker and kubernets, Detected Vulnerability (CVE-2021-30465), allowing you to access the container to the main file system of the host environment. Through manipulations with symbolic references, you can prepare on the form of the harmless configuration of the container, which will lead to BIND-mounting the external FS inside the container. The problem is eliminated in updating Runc 1.0.0-RC95 .
To operate the vulnerability, the attacker must be able to run containers with additional mounting points in the configuration (for example, the problem is played in the KUBERNETES database environments in which users can run their containers).
Due to the presence of a temporary window between the check and using the mount points to the partitions, shared with other containers, the attacker may take advantage of the race status and replace the symbolic reference to the area used when mounting the container in the container in the container.