Critical RCE Vulnerabilities in React and Next.js

>>gonepi+(OP)
It seems like this vulnerability is yet another prototype pollution vulnerability.

There was a TC39 proposal a few years ago [0] that proposed to block the getting/setting of object prototypes using the bracket notation, which would have prevented this vulnerability.

At the moment, every single get/set with a square bracket, which uses untrusted data, needs to do some manual check to see whether variables contain "bad" keys like `__proto__`, `prototype,` `constructor`, and so on. This is incredibly annoying, and doesn't really fix the issue. It's possible also to freeze an object's prototype, but that causes other issues. It's also possible to use Object.create(null), and Object.hasOwn (also known as Object.prototype.hasOwnProperty), but again, this does not scale because it has to be done _every single time_.

Maybe it's time to revisit this from a language perspective, instead of continuous bandaid fixes for this language-specific vulnerability (a similar language-specific vulnerability exists in Python called class pollution, but it's .. extremely uncommon).

[0]: https://github.com/tc39/proposal-symbol-proto

>>mmsc+Jk
Note however, that proposal does not cover some other types of prototype pollution, such as:

  > let config = {};
  > Object.assign(config, JSON.parse('{"__proto__": {"isAdmin": true}}'));
  console.log({}.isAdmin); // true!

or:

  > console.log({}['constructor'] ? {}['constructor']('THIS MUST NOT BE EXPOSED') :  'pub')
  [String: 'THIS MUST NOT BE EXPOSED']

zlacker