SysmonElixir is a system monitor HTTP service in Elixir. Prior to version 1.0.1, the /read endpoint reads any file from the server's /etc/passwd by default. In v1.0.1, a whitelist was added that limits reading to only files under priv/data. This issue has been patched in version 1.0.1.
https://github.com/bocaletto-luca/elixir-system-monitor/security/advisories/GHSA-9vj4-rv7q-36qj