cve/2021/CVE-2021-23436.md

### [CVE-2021-23436](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23436)
![](https://img.shields.io/static/v1?label=Product&message=immer&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%209.0.6%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Prototype%20Pollution&color=brighgreen)

### Description

This affects the package immer before 9.0.6. 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.

### POC

#### Reference
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579266
- https://snyk.io/vuln/SNYK-JS-IMMER-1540542

#### Github
- https://github.com/ARPSyndicate/cvemon
- https://github.com/broxus/ever-wallet-browser-extension
- https://github.com/broxus/ever-wallet-browser-extension-old
- https://github.com/dellalibera/dellalibera
- https://github.com/grafana/plugin-validator
- https://github.com/khulnasoft/plugin-validator