'use strict'; const Express = require('express'); const BodyParser = require('body-parser'); const Mongoose = require('mongoose'); Mongoose.Promise = global.Promise; Mongoose.connect('mongodb://localhost/injectable1'); const app = Express(); app.use(BodyParser.json()); const Document = Mongoose.model('Document', { title: { type: String, unique: true }, type: String }); app.post('/documents/find', (req, res) => { const query = {}; query.title = req.body.title; // NOT OK: query is tainted by user-provided object value Document.find(query); });