Mageia: 2019-0068 Moderate: opencontainers-runc Memory Modification Issue

Not using pivot_root(2) leaves the host /proc around in the mount namespace so that it is possible to mount another /proc without any other submount, even if /proc in the container is not fully visible. This flaw allows an attacker to read and modify some parts of the Linux kernel memory (rhbz#1663068).
runc through 1.0-rc6 allows attackers to overwrite the host runc binary (and consequently obtain host root access) by leveraging the ability to execute a command as root within one of these types of containers: a new container with an attacker-controlled image, or an existing container, to which the attacker previously had write access, that can be attached with docker exec. This occurs because of file-descriptor mishandling, related to /proc/self/exe (CVE-2019-5736).