cve/2021/CVE-2021-4138.md

### [CVE-2021-4138](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4138)
![](https://img.shields.io/static/v1?label=Product&message=geckodriver&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%200.30.0%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Fixed%20a%20DNS%20rebinding%20issues%20by%20enforcing%20a%20stricter%20Host%20header%20check.&color=brighgreen)

### Description

Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.

### POC

#### Reference
- https://bugzilla.mozilla.org/show_bug.cgi?id=1652612

#### Github
No PoCs found on GitHub currently.