This is the check_statusfile Nagios plugi plugin, available e.g. in /usr/lib/nagios/plugins/. The read file content is limited to the first line.

File read

It reads data from files, it may be used to do privileged reads or disclose files outside a restricted file system.

LFILE=file_to_read
check_statusfile $LFILE

Sudo

If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.

LFILE=file_to_read
sudo check_statusfile $LFILE