Unauthenticated arbitrary file upload on the https://█████/ (█████.mil)

How it was found

Description

I was able to identify unsafe upload endpoint on the https://██████/upload.php

POC

1. Go to the https://██████/upload.php
2. Upload some test file. You will see success message, leaking some internal paths
3. Visit https://██████████/delete.me and you will see your uploaded file there I uploaded example image file there: █████

Impact

Arbitrary file upload, may lead to the Stored XSS, hosting attacker's content and code execution.