time bomb

noun
  1. 1

    A bomb that has a mechanism such that detonation can be preset to a particular time.

  2. 2

    A program designed to perform a destructive action at a certain date and/or time.

  3. 3

    A situation that threatens to have disastrous consequences at some future time.

Source: https://en.wiktionary.org/wiki/time%20bomb