cve/2024/CVE-2024-45614.md

### [CVE-2024-45614](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-45614)
![](https://img.shields.io/static/v1?label=Product&message=puma&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%205.6.9%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=%3E%3D%206.0.0%2C%20%3C%206.4.3%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-639%3A%20Authorization%20Bypass%20Through%20User-Controlled%20Key&color=brightgreen)

### Description

Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables is affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Users are advised to upgrade. Nginx has a underscores_in_headers configuration variable to discard these headers at the proxy level as a mitigation. Any users that are implicitly trusting the proxy defined headers for security should immediately cease doing so until upgraded to the fixed versions.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/nomi-sec/PoC-in-GitHub
- https://github.com/ooooooo-q/puma_header_normalization-CVE-2024-45614