Arbitrary file write via authenticated OSDP file upload

An authenticated attacker can upload a file with a filename including “..” and “/” to achieve the ability to upload the desired file anywhere on the filesystem. This vulnerability impacts products based on HID Mercury Intelligent Controllers LP1501, LP1502, LP2500, LP4502, and EP4502 which contain firmware versions prior to 1.271. This allows a malicious actor to overwrite sensitive system files and install a startup service to gain remote access to the underlaying Linux operating system with root privileges.