Integers
Defects in integer arithmetic, where a computed value exceeds the range its type can hold. The central case is overflow: a sum, product, or accumulation that grows past the type’s maximum wraps around to a small or negative value instead of failing, and that wrapped result then flows into sizes, indices, or allocation lengths.
Because the wrap is silent and deterministic, the bug is invisible until the operands grow large enough to trigger it, at which point it manifests as corrupted state or an exploitable size miscalculation.