SunOS sendmail 5.59 through 5.65 uses popen to process a forwarding host argument, which allows local users to gain root privileges by modifying the IFS (Internal Field Separator) variable and passing crafted values to the -oR option.
The permissions for the /dev/audio device on Solaris 2.2 and earlier, and SunOS 4.1.x, allow any local user to read from the device, which could be used by an attacker to monitor conversations happening near a machine that has a microphone.