Overstating rhymes with:
understating, devastating, understating, agitating, debilitating, devastating, dictating, facilitating, gravitating, hesitating, imitating, incapacitating, irritating, levitating, meditating, necessitating, permutating, precipitating, rehabilitating, resuscitating, rotating, understating
Overstating sounds like:
overexciting, overreacting, overshadowing, overshooting