The average phpBB or Wordpress, even if it's behind cloudflare, probably has a direct IPv4 that's not disabled.
This is a storm, but hopefully quick to blow over with a panic frency of apt update or docker build.
The immediate exposure is faar worse here though, since its by design internet facing code.
A college enabled logging on their server as soon as they saw the news, and got dozens of attempted requests against index.php.