Dumb Drop is a file upload application. Users with permission to upload to the service are able to exploit a path traversal vulnerability to overwrite arbitrary system files. As the container runs as root by default, there is no limit to what can be overwritten. With this, it's possible to inject malicious payloads into files ran on schedule or upon certain service actions. As the service is not required to run with authentication enabled, this may permit wholly unprivileged users root access. Otherwise, anybody with a PIN.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.