addnetpr in IRIX 5.3 and 6.2 allows local users to overwrite arbitrary files and possibly gain root privileges via a symlink attack on the printers temporary file.
serial_ports administrative program in IRIX 4.x and 5.x trusts the user's PATH environmental variable to find and execute the ls program, which allows local users to gain root privileges via a Trojan horse ls program.
rdist in various UNIX systems uses popen to execute sendmail, which allows local users to gain root privileges by modifying the IFS (Internal Field Separator) variable.