diff --git a/CHANGELOG b/CHANGELOG
index 5b9f82093..87420a650 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE][GH#1720] Function marshall_dom_sid2 in library msrpctypes was not
+  correctly populating ID Authority. [nnposter]
+
 o [NSE][GH#1720] Unmarshalling functions in library msrpctypes were attempting
   arithmetic on a nil argument. [Ivan Ivanov, nnposter]
 
diff --git a/nselib/msrpctypes.lua b/nselib/msrpctypes.lua
index 8300fac4d..0cc4fea1b 100644
--- a/nselib/msrpctypes.lua
+++ b/nselib/msrpctypes.lua
@@ -1655,7 +1655,7 @@ function marshall_dom_sid2(sid)
   result = {
     -- TODO: Is the first 32-bit integer here supposed to be num_auths, or some
     -- other count value?
-    string.pack("<I4BB>I6", sid_array.num_auths, sid_array.sid_rev_num, sid_array.num_auths, sid_array.authority),
+    string.pack("<I4BB>I6", sid_array.num_auths, sid_array.sid_rev_num, sid_array.num_auths, sid_array.authority_high),
   }
   for i = 1, sid_array['num_auths'], 1 do
     result[#result+1] = string.pack("<I4", sid_array['sub_auths'][i])