Test patching sudo in your old horrible CentOS 6 instance

Dockerfile

FROM centos:6
# This works, but don't use yum update, it'll update too many packages
RUN CENTOSVER=`cat /etc/centos-release | grep 'CentOS release' | awk '{print $3}'` ; \
    grep -v mirrorlist /etc/yum.repos.d/CentOS-Base.repo \
    | sed -e 's/^#baseurl=/baseurl=/g' \
    | sed -e "s?baseurl=http://mirror.centos.org/centos/\$releasever/?baseurl=https://vault.centos.org/$CENTOSVER/?g" \
    > /etc/yum.repos.d/CentOS-Base.repo.new ; \
    mv -f /etc/yum.repos.d/CentOS-Base.repo.new /etc/yum.repos.d/CentOS-Base.repo
RUN curl -L -o sudo-patched.rpm https://github.com/sudo-project/sudo/releases/download/SUDO_1_9_5p2/sudo-1.9.5-3.el6.x86_64.rpm
RUN yum install -y sudo && rpm -qi sudo && sudo -V
RUN rpm -ev sudo && rpm -Uvh sudo-patched.rpm && rpm -qi sudo && sudo -V
RUN rpm -ev sudo && yum install -y sudo && rpm -qi sudo && sudo -V