In the web interface of Parallels Remote Application Server (RAS) 15.5 Build 16140, a vulnerability exists due to improper validation of the file path when requesting a resource under the "RASHTML5Gateway" directory. A remote, unauthenticated attacker could exploit this weakness to read arbitrary files from the vulnerable system using path traversal sequences.
https://www.exploit-db.com/exploits/442321/
https://euvd.enisa.europa.eu/vulnerability/EUVD-2017-18380
https://blog.runesec.com/2018/02/22/parallels-ras-path-traversal/