netprint in SGI IRIX 6.4 and earlier trusts the PATH environmental variable for finding and executing the disable program, which allows local users to gain privileges.
Indigo Magic System Tour in the SGI system tour package (systour) for IRIX 5.x through 6.3 allows local users to gain root privileges via a Trojan horse .exitops program, which is called by the inst command that is executed by the RemoveSystemTour program.
Buffer overflow in lpr, as used in BSD-based systems including Linux, allows local users to execute arbitrary code as root via a long -C (classification) command line option.
Telnet allows a remote client to specify environment variables including LD_LIBRARY_PATH, allowing an attacker to bypass the normal system libraries and gain root access.