AR 600-8-22 (2011) says:
" f. Second and third awards of the CIB are indicated by superimposing 1 and 2 stars respectively, centered at the top
of the badge between the points of the oak wreath. To date, a separate award of the CIB has been authorized for
qualified Soldiers in the following qualifying periods:
(1) World War II (7 December 1941 to 3 September 1945).
(2) The Korean Conflict (27 June 1950 to 27 July 1953).
(3) The Republic of Vietnam Conflict. Service in the Republic of Vietnam conflict (2 March 1961 to 28 March
1973) combined with qualifying service in Laos; Dominican Republic; Korea on the DMZ; El Salvador; Grenada; Joint
Security Area, Panmunjom, Korea; Panama; Southwest Asia Conflict; and Somalia, regardless of whether a Soldier has
served one or multiple tours in any or all of these areas. The Republic of Vietnam Conflict Era officially terminated on
10 March 1995.
(4) War on Terrorism (Afghanistan, Operation ENDURING FREEDOM) and (Iraq, Operation IRAQI FREEDOM).
g. Subsequent awards of the CIB is not authorized for the same qualifying period, as outlined above."
So, definitely possible and authorized.