CVEs-PoC/2021/CVE-2021-23438.md

### [CVE-2021-23438](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23438)
![](https://img.shields.io/static/v1?label=Product&message=mpath&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%200.8.4%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Prototype%20Pollution&color=brighgreen)

### Description

This affects the package mpath before 0.8.4. A type confusion vulnerability can lead to a bypass of CVE-2018-16490. In particular, the condition ignoreProperties.indexOf(parts[i]) !== -1 returns -1 if parts[i] is ['__proto__']. This is because the method that has been called if the input is an array is Array.prototype.indexOf() and not String.prototype.indexOf(). They behave differently depending on the type of the input.

### POC

#### Reference
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579548
- https://snyk.io/vuln/SNYK-JS-MPATH-1577289

#### Github
- https://github.com/dellalibera/dellalibera