Security when sending and retrieving data from a URL

Hello, I am learning development and I do not know much about security. I'm doing a web application using Nodejs + Expressjs + AngularJs + MongoDB . I did as follows, the MongoDB data is sent to a URL using the Post method, and then I "access" that data with AngularJs and display it on the screen. I wonder how insecure this is. Here is the code:

First I created a Schema from my MongoDB collection:

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var userSchema = new Schema({
    nome: String,
    idade: Number,
    CPF: String,
    email: String
});

var User = mongoose.model('User' , userSchema );

module.exports = User;

Then I got this Schema in a file and created a URL and sent the data using POST method

var express = require('express');
var router = express.Router();
var mongoose = require('mongoose');
var User = require('../models/users');

//Se aqui for router.get os dados serão exibidos na URL localhost/api/users
//Então usei router.post
router.post('/api/users' , function(req, res, next){
  User.find(function(err, users){
    res.json(users);
 });
});

module.exports = router;

Finally, I got the data from the URL and displayed on the screen with Angular:

app.controller("RBScontroller", function ($scope, $http) {

    $scope.enviar = function enviar(){

        var ApiMongo = 'http://localhost:3000/api/users';
        $scope.users = [];
        $scope.loading = true;      

        $http.post(ApiMongo).success(function(data) {
            console.log(data);
            $scope.users = data;
            $scope.loading = false;             

        }).error(function(msg) {      

            angular.element($(function(){alert("Fail")}));
            $scope.loading = false;
        });
    }   
});

Does this method leave the data exposed in any way? Thanks