When a vacancy occurs in the office of sheriff of any county, the undersheriff of such county shall in all things execute the office of sheriff until a sheriff is appointed or elected and qualified. Any default or misfeasance in office of such undersheriff in the meantime, as well as before such vacancy, shall be deemed to be a breach of the condition of the bond given by the sheriff who appointed the undersheriff or the insurance policy purchased by the county on the sheriff's behalf.
C.R.S. § 30-10-505
For powers, duties, and compensation of person acting as sheriff when the office is vacant, see §§ 30-10-106, 30-10-518, and 30-10-604.