CVEs-PoC/2021/CVE-2021-21322.md

### [CVE-2021-21322](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21322)
![](https://img.shields.io/static/v1?label=Product&message=fastify-http-proxy&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%204.3.1%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-20%20Improper%20Input%20Validation&color=brightgreen)

### Description

fastify-http-proxy is an npm package which is a fastify plugin for proxying your http requests to another server, with hooks. By crafting a specific URL, it is possible to escape the prefix of the proxied backend service. If the base url of the proxied server is `/pub/`, a user expect that accessing `/priv` on the target service would not be possible. In affected versions, it is possible. This is fixed in version 4.3.1.

### POC

#### Reference
- https://www.npmjs.com/package/fastify-http-proxy

#### Github
- https://github.com/ARPSyndicate/cvemon