SunOS 4.1.4 on a Sparc 20 machine allows local users to cause a denial of service (kernel panic) by reading from the /dev/tcx0 TCX device.
cmdtool in OpenWindows 3.0 and XView 3.0 in SunOS 4.1.4 and earlier allows attackers with physical access to the system to display unechoed characters (such as those from password prompts) via the L2/AGAIN key.