Seems a lot of people will need to upgrade Apache today.
"In Apache HTTP Server 2.4 releases 2.4.17 to 2.4.38, with MPM event, worker or prefork, code executing in less-privileged child processes or threads (including scripts executed by an in-process scripting interpreter) could execute arbitrary code with the privileges of the parent process (usually root) by manipulating the scoreboard. Non-Unix systems are not affected."
https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2019-0211