GHSA-mh6w-vxff-9wqp: PHPUnit: Argument injection via newline in PHP INI values forwarded to child processes

PHPUnit forwards PHP INI settings to child processes (used for isolated/PHPT test execution) as -d name=value command-line arguments without neutralizing INI metacharacters. Because PHP’s INI parser interprets " as a string delimiter, ; as the start of a comment, and most importantly a newline as a directive separator, a value containing a newline is parsed by the child process as multiple INI directives.

An attacker able to influence a single INI value can therefore inject arbitrary additional directives into the child’s configuration, including auto_prepend_file, extension, disable_functions, open_basedir, and others. Setting auto_prepend_file to an attacker-controlled path yields remote code execution in the child process.

Sources of INI values that participate in the attack:

• <ini name="…" value="…"/> entries in phpunit.xml / phpunit.xml.dist
• INI settings inherited from the host PHP runtime via ini_get_all()