size_t php_mysqlnd_sha256_pk_request_write(void * _packet, MYSQLND_CONN_DATA * conn TSRMLS_DC)
{
	zend_uchar buffer[MYSQLND_HEADER_SIZE + 1];
	size_t sent;

	DBG_ENTER("php_mysqlnd_sha256_pk_request_write");

	int1store(buffer + MYSQLND_HEADER_SIZE, '\1');
	sent = conn->net->data->m.send_ex(conn->net, buffer, 1, conn->stats, conn->error_info TSRMLS_CC);

	DBG_RETURN(sent);
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.