This executable can read data from local files.
This function can be performed by any unprivileged user.
whiptail --textbox --scrolltext /path/to/input-file 0 0
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
whiptail --textbox --scrolltext /path/to/input-file 0 0
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
whiptail --textbox --scrolltext /path/to/input-file 0 0