CVEs-PoC/2021/CVE-2021-21705.md

### [CVE-2021-21705](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21705)
![](https://img.shields.io/static/v1?label=Product&message=PHP&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=7.3.x%3C%207.3.29%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-20%20Improper%20Input%20Validation&color=brighgreen)

### Description

In PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21 and 8.0.x below 8.0.8, when using URL validation functionality via filter_var() function with FILTER_VALIDATE_URL parameter, an URL with invalid password field can be accepted as valid. This can lead to the code incorrectly parsing the URL and potentially leading to other security implications - like contacting a wrong server or making a wrong access decision.

### POC

#### Reference
- https://www.oracle.com/security-alerts/cpujan2022.html

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