The server has just executed the id command. The attacker now has Remote Code Execution (RCE).
Risk
The vulnerability arises because the script blindly reads from php://stdin and passes the content directly to the eval() function. Crucially, this file is not protected by an authentication check or a mechanism to prevent web access. vendor phpunit phpunit src util php eval-stdin.php exploit
PHPUnit is the de facto standard for unit testing in PHP applications. Developers use it to write and run tests that ensure individual units of source code (like functions or methods) behave as expected. It is typically installed as a via Composer. The server has just executed the id command
The exploit is trivial to execute. An attacker sends a POST request to the location of eval-stdin.php with a payload in the body. vendor phpunit phpunit src util php eval-stdin.php exploit