diff --git a/nselib/asn1.lua b/nselib/asn1.lua
index 207d212a8..0aa81fb7d 100644
--- a/nselib/asn1.lua
+++ b/nselib/asn1.lua
@@ -61,7 +61,7 @@ ASN1Decoder = {
 
     -- Boolean
     self.decoder["01"] = function( self, encStr, elen, pos )
-      local val = bin.unpack("H", encStr, pos)
+      local pos, val = bin.unpack("H", encStr, pos)
       if val ~= "FF" then
         return pos, true
       else
diff --git a/nselib/mongodb.lua b/nselib/mongodb.lua
index 79505e6c9..545efc7f5 100644
--- a/nselib/mongodb.lua
+++ b/nselib/mongodb.lua
@@ -676,7 +676,7 @@ end
 --   local res
 --   res = versionQuery()
 --   print(type(res),res:len(),res)
---   local  out= bin.unpack('C'..#res,res)
+--   local _, out= bin.unpack('C'..#res,res)
 --   printBuffer(res)
 -- end
 --test()
diff --git a/nselib/smbauth.lua b/nselib/smbauth.lua
index 2e8f77b5b..2edb17667 100644
--- a/nselib/smbauth.lua
+++ b/nselib/smbauth.lua
@@ -932,7 +932,8 @@ function get_host_info_from_security_blob(security_blob)
         break
       elseif ( av_id == NTLM_AV_ID_VALUES.MsvAvTimestamp ) then
         -- this is a FILETIME value (see [MS-DTYP]), representing the time in 100-ns increments since 1/1/1601
-        ntlm_challenge[ friendly_name ] = bin.unpack( "<L", value )
+        local _
+        _, ntlm_challenge[ friendly_name ] = bin.unpack( "<L", value )
       elseif ( friendly_name ) then
         ntlm_challenge[ friendly_name ] = unicode.utf16to8( value )
       end
diff --git a/nselib/sslcert.lua b/nselib/sslcert.lua
index 052db2168..8cc0cc7e7 100644
--- a/nselib/sslcert.lua
+++ b/nselib/sslcert.lua
@@ -466,7 +466,7 @@ StartTLS = {
     while optype ~= mssql.PreLoginPacket.OPTION_TYPE.Terminator do
       --stdnse.debug1("optype: %d, oppos: %x, oplen: %d", optype, oppos, oplen)
       if optype == mssql.PreLoginPacket.OPTION_TYPE.Encryption then
-        encryption = bin.unpack('C', result, oppos + 1)
+        pos, encryption = bin.unpack('C', result, oppos + 1)
         break
       end
       pos, optype, oppos, oplen = bin.unpack('>CSS', result, pos)