PHP Uncontrolled Resource Consumption Vulnerability - CVE-2015-9253

An issue was discovered in PHP 7.3.x before 7.3.0alpha3 7.2.x before 7.2.8 and before 7.1.20. The php-fpm master process restarts a child process in an endless loop when using program execution functions (e.g. passthru exec shell_exec or system) with a non-blocking STDIN stream causing this master process to consume 100 of the CPU and consume disk space with a large volume of error logs as demonstrated by an attack by a customer of a shared-hosting facility.