Pretty much that, ICBM warheads are travelling at around Mach-25 just before re-entry and then slow rapidly as they decend to the target, these missiles are doing Mach-5 plus at very high altitude and also slow down in the final flight stage, not much can exceed Mach-3 for long at lower levels, especially not a glider.
'Hypersonic missiles' are being touted as the new global threat, one of those made up titles used to impress non engineers at budget time. The Russian KH22* anti ship cruise missile (operational since the 1960s) can manage well over Mach-4 during its mid flight phase, these are just faster and longer ranged. The response will be also be faster longer ranged missiles.
*A Major driver in developing the F14 & AIM54 system.