The create_response function in server/server.c in Psensor before 1.1.4 allows Directory Traversal because it lacks a check for whether a file is under the webserver directory.
https://lists.debian.org/debian-lts-announce/2018/04/msg00026.html
http://git.wpitchoune.net/gitweb/?p=psensor.git%3Ba=blob%3Bf=NEWS