https://example.com/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php They can send arbitrary PHP code via POST or query parameters if the script is misconfigured to read from php://input instead of php://stdin (some outdated forks do this). Using curl :
curl -X POST --data "<?php system('id'); ?>" \ https://example.com/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php If the server misinterprets php://stdin (in a CGI/FastCGI setup), it may read the POST body — leading to . https://example
find /var/www/html -name "eval-stdin.php" If found outside vendor (e.g., moved to web/ ), investigate immediately. Test if the file is reachable: moved to web/ )