# CVE-2021-36873

## Description
Authenticated Persistent Cross-Site Scripting (XSS) vulnerability in WordPress iQ Block Country plugin (versions <= 1.2.11). Vulnerable parameter: `&blockcountry_blockmessage`.

## CVSS (Vector and Score)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N - 5.5 MEDIUM

## Affected Application
WordPress iQ Block Country plugin

## Affected Version
<= 1.2.11

## Total Installation
30,000+

## Steps to Reproduce
1. Login as administrator
2. Go to http://localhost/wp-admin/options-general.php?page=iq-block-country%2Flibs%2Fblockcountry-settings.php
3. Find `Message to display when people are blocked:` form
4. Input `</textarea><script>alert(1)</script>`
5. Scroll down and press `Save Changes` button

## Proof of Concept
- Video

> https://youtu.be/WtOiHY5R-t0

- Image
![image](https://user-images.githubusercontent.com/36522826/202700374-52d36350-adff-4fe3-b46d-21f08955e8c6.png)