runc through 1.0.0-rc8, as used in Docker through 19.03.2-ce and other products, allows AppArmor restriction bypass because libcontainer/rootfs_linux.go incorrectly checks mount targets, and thus a malicious Docker image can mount over a /proc directory.
{
    "binaries": [
        {
            "binary_name": "golang-github-opencontainers-runc-dev",
            "binary_version": "1.0.0~rc7+git20190403.029124da-0ubuntu1~16.04.4+esm2"
        },
        {
            "binary_name": "runc",
            "binary_version": "1.0.0~rc7+git20190403.029124da-0ubuntu1~16.04.4+esm2"
        }
    ],
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}