diff --git a/scripts/snmp-ios-config.nse b/scripts/snmp-ios-config.nse
index 5708ab32b..bb242bdd0 100644
--- a/scripts/snmp-ios-config.nse
+++ b/scripts/snmp-ios-config.nse
@@ -179,6 +179,9 @@ action = function(host, port)
 
   local result
   result = snmp.fetchFirst(response)
+  if not result then
+    return
+  end
 
   if result == 3 then
     result = ( infile and infile:getContent() )
diff --git a/scripts/snmp-sysdescr.nse b/scripts/snmp-sysdescr.nse
index 4616bc5d8..0122f16e7 100644
--- a/scripts/snmp-sysdescr.nse
+++ b/scripts/snmp-sysdescr.nse
@@ -93,6 +93,9 @@ action = function(host, port)
   try(socket:close())
 
   local uptime = snmp.fetchFirst(response)
+  if not uptime then
+    return
+  end
 
   local days, hours, minutes, seconds, htime, mtime, stime
   days = math.floor(uptime / 8640000)