Division
Defects in integer and floating-point division, where the divisor or the operation itself is unsafe. The dominant case is a divisor that can reach zero, which traps the process on most integer hardware and yields infinities or NaNs in floating point — a reliable crash or a silently poisoned result depending on the type.
The root cause is usually a divisor that is computed or read from input without a prior check that it is non-zero, so the guard the operation needs is simply missing on some path.