A buffer overflow vulnerability was found in PHP when processing passwords in mysqlnd/pdo in mysqlnd_wireprotocol.c. When using the pdo_mysql extension with mysqlnd driver, if the third party is allowed to supply a password to the host for the connection, a password of excessive length can trigger a buffer overflow in PHP. This flaw allows a remote attacker to pass a password (with an excessive length) via PDO to the MySQL server, triggering arbitrary code execution on the target system.