Triple fault - Definition

A triple fault is a special kind of exception generated by the CPU when an exception occurs while the CPU is trying to invoke the double fault exception handler, which itself handles exceptions occurring while trying to invoke a regular exception handler.

Intel x86 processors beginning with the 80286 will cause a SHUTDOWN cycle to occur when a triple fault is hit, which typically leads to the motherboard hardware initiating a reset of the CPU and in turn the whole computer.