This might not be the best place to ask, but is there a reason why the instructions above for testing are only for using dnf meaning it won't work for centos users? Especially for a RCE being exploited in the wild, giving all users instructions to test/upgrade would be nicer. (eg yum update --enablerepo=epel-testing exim)

I appreciate this probably isn't the best place to ask. If someone can advise a better location I can ask there.