diff --git a/nselib/http.lua b/nselib/http.lua
index 67ed8431a..a1bc9944d 100644
--- a/nselib/http.lua
+++ b/nselib/http.lua
@@ -201,7 +201,7 @@ local function get_quoted_string(s, offset, crlf)
       c = s:sub(i, i)
       if c == "" then
         -- No character following.
-        error(string.format("\\ escape at end of input while parsing quoted-string."))
+        error("\\ escape at end of input while parsing quoted-string.")
       end
       -- Only CHAR may follow a backslash.
       if c:byte(1) > 127 then
@@ -2543,13 +2543,13 @@ function identify_404(host, port)
       if(clean_body ~= clean_body2) then
         stdnse.debug1("HTTP: Two known 404 pages returned valid and different pages; unable to identify valid response.")
         stdnse.debug1("HTTP: If you investigate the server and it's possible to clean up the pages, please post to nmap-dev mailing list.")
-        return false, string.format("Two known 404 pages returned valid and different pages; unable to identify valid response.")
+        return false, "Two known 404 pages returned valid and different pages; unable to identify valid response."
       end
 
       if(clean_body ~= clean_body3) then
         stdnse.debug1("HTTP: Two known 404 pages returned valid and different pages; unable to identify valid response (happened when checking a folder).")
         stdnse.debug1("HTTP: If you investigate the server and it's possible to clean up the pages, please post to nmap-dev mailing list.")
-        return false, string.format("Two known 404 pages returned valid and different pages; unable to identify valid response (happened when checking a folder).")
+        return false, "Two known 404 pages returned valid and different pages; unable to identify valid response (happened when checking a folder)."
       end
 
       return true, 200, clean_body
diff --git a/nselib/jdwp.lua b/nselib/jdwp.lua
index 92a05b08c..55dee9f2c 100644
--- a/nselib/jdwp.lua
+++ b/nselib/jdwp.lua
@@ -170,7 +170,7 @@ JDWPReplyPacket = {
     if flags == 0x80 then
       return true, JDWPReplyPacket:new(length,id,error_code,data)
     end
-    stdnse.debug2("JDWP error parsing reply. Wrong reply packet flag. Raw data: ", stdnse.tohex(reply_packet))
+    stdnse.debug2("JDWP error parsing reply. Wrong reply packet flag. Raw data: %s", stdnse.tohex(reply_packet))
     return false, "JDWP error parsing reply."
   end
 
diff --git a/nselib/msrpc.lua b/nselib/msrpc.lua
index b6bfa0dd1..a84ab47a7 100644
--- a/nselib/msrpc.lua
+++ b/nselib/msrpc.lua
@@ -1659,7 +1659,7 @@ function samr_querydisplayinfo(smbstate, domain_handle, index, count)
     return false, result
   end
 
-  stdnse.debug3("MSRPC: QueryDisplayInfo() returned successfully", i)
+  stdnse.debug3("MSRPC: QueryDisplayInfo() returned successfully")
 
   -- Make arguments easier to use
   arguments = result['arguments']
@@ -4313,7 +4313,7 @@ function service_create(host, servicename, path)
   end
 
   -- Create the service
-  stdnse.debug2("Creating the service", servicename)
+  stdnse.debug2("Creating the service")
   status, create_result = svcctl_createservicew(smbstate, open_result['handle'], servicename, servicename, path)
   if(status == false) then
     smb.stop(smbstate)
diff --git a/nselib/rpc.lua b/nselib/rpc.lua
index 7bead8ec3..d78418e6d 100644
--- a/nselib/rpc.lua
+++ b/nselib/rpc.lua
@@ -374,8 +374,7 @@ Comm = {
       local tmp
       status, tmp = self:GetAdditionalBytes( data, pos, HEADER_LEN - ( data:len() - pos ) )
       if not status then
-        stdnse.debug4(
-          string.format("Comm.DecodeHeader: failed to call GetAdditionalBytes"))
+        stdnse.debug4("Comm.DecodeHeader: failed to call GetAdditionalBytes")
         return -1, nil
       end
       data = data .. tmp
@@ -394,8 +393,7 @@ Comm = {
     if header.verifier.length - 8 > 0 then
       status, data = self:GetAdditionalBytes( data, pos, header.verifier.length - 8 )
       if not status then
-        stdnse.debug4(
-          string.format("Comm.DecodeHeader: failed to call GetAdditionalBytes"))
+        stdnse.debug4("Comm.DecodeHeader: failed to call GetAdditionalBytes")
         return -1, nil
       end
       pos, header.verifier.data = bin.unpack("A" .. header.verifier.length - 8, data, pos )
diff --git a/scripts/afp-ls.nse b/scripts/afp-ls.nse
index 7e9e82422..e9761082e 100644
--- a/scripts/afp-ls.nse
+++ b/scripts/afp-ls.nse
@@ -135,7 +135,7 @@ action = function(host, port)
     end
 
     if ( not status ) then
-      stdnse.debug1("Login failed", response)
+      stdnse.debug1("Login failed")
       stdnse.debug3("Login error: %s", response)
       return
     end
diff --git a/scripts/afp-path-vuln.nse b/scripts/afp-path-vuln.nse
index 2d34886dc..6415c2019 100644
--- a/scripts/afp-path-vuln.nse
+++ b/scripts/afp-path-vuln.nse
@@ -176,7 +176,7 @@ Directory traversal vulnerability in AFP Server in Apple Mac OS X before
       status, response = afp_helper:Login(nil, nil)
     end
     if ( not(status) ) then
-      stdnse.debug1("Login failed", response)
+      stdnse.debug1("Login failed")
       stdnse.debug3("Login error: %s", response)
       return
     end
diff --git a/scripts/afp-showmount.nse b/scripts/afp-showmount.nse
index f73018461..865fc463b 100644
--- a/scripts/afp-showmount.nse
+++ b/scripts/afp-showmount.nse
@@ -73,7 +73,7 @@ action = function(host, port)
     end
 
     if ( not status ) then
-      stdnse.debug1("Login failed", response)
+      stdnse.debug1("Login failed")
       stdnse.debug3("Login error: %s", response)
       return
     end
diff --git a/scripts/http-form-brute.nse b/scripts/http-form-brute.nse
index b0e5f5117..c907cc2f0 100644
--- a/scripts/http-form-brute.nse
+++ b/scripts/http-form-brute.nse
@@ -324,7 +324,7 @@ action = function (host, port)
     return stdnse.format_output(false, string.format("Failed to submit the form to path %q", path))
   end
   if success then
-    return stdnse.format_output(false, string.format("Failed to recognize failed authentication. See http-form-brute.onsuccess and http-form-brute.onfailure"))
+    return stdnse.format_output(false, "Failed to recognize failed authentication. See http-form-brute.onsuccess and http-form-brute.onfailure")
   end
 
   local engine = brute.Engine:new(Driver, host, port, options)
diff --git a/scripts/http-tplink-dir-traversal.nse b/scripts/http-tplink-dir-traversal.nse
index 23784a526..2aac55d4f 100644
--- a/scripts/http-tplink-dir-traversal.nse
+++ b/scripts/http-tplink-dir-traversal.nse
@@ -98,7 +98,7 @@ local function check_vuln(host, port)
   stdnse.debug1("HTTP GET %s", evil_uri)
   local response = http.get(host, port, evil_uri)
   if response.body and response.status==200 and response.body:match("root:") then
-    stdnse.debug1("Pattern 'root:' found.", response.body)
+    stdnse.debug1("Pattern 'root:' found.")
     return true
   end
   return false
diff --git a/scripts/http-vuln-cve2011-3368.nse b/scripts/http-vuln-cve2011-3368.nse
index 4e3e6e7bd..6a47a95ad 100644
--- a/scripts/http-vuln-cve2011-3368.nse
+++ b/scripts/http-vuln-cve2011-3368.nse
@@ -152,7 +152,7 @@ servers to remote users who send carefully crafted requests.]],
   end
 
   -- TEST 3: The external website test. This does not mean that you can reach a LAN ip, but this is a relevant issue anyway.
-  local external = http.get(host,port, ("@scanme.nmap.org"):format(prefix))
+  local external = http.get(host,port, ("%s@scanme.nmap.org"):format(prefix))
   if ( external.status == 200 and string.match(external.body,"Go ahead and ScanMe") ) then
     vuln.extra_info = "Proxy allows requests to external websites"
   end
diff --git a/scripts/http-wordpress-enum.nse b/scripts/http-wordpress-enum.nse
index 4f0a19167..2b6586bac 100644
--- a/scripts/http-wordpress-enum.nse
+++ b/scripts/http-wordpress-enum.nse
@@ -125,7 +125,7 @@ local function get_version(path, typeof, host, port)
   if versioncheck.body then
     version = versioncheck.body:match(pattern)
   end
-  stdnse.debug1("Version found:", version)
+  stdnse.debug1("Version found: %s", version)
   return version
 end
 
diff --git a/scripts/ipv6-ra-flood.nse b/scripts/ipv6-ra-flood.nse
index 1778a875f..5a35214da 100644
--- a/scripts/ipv6-ra-flood.nse
+++ b/scripts/ipv6-ra-flood.nse
@@ -61,7 +61,7 @@ prerule = function()
   end
 
   if not stdnse.get_script_args(SCRIPT_NAME .. ".interface") and not nmap.get_interface() then
-    stdnse.debug1("No interface was selected, aborting...", SCRIPT_NAME)
+    stdnse.debug1("No interface was selected, aborting...")
     return false
   end
 
diff --git a/scripts/ms-sql-empty-password.nse b/scripts/ms-sql-empty-password.nse
index 7cfb6fefb..3fefe9506 100644
--- a/scripts/ms-sql-empty-password.nse
+++ b/scripts/ms-sql-empty-password.nse
@@ -81,7 +81,7 @@ local function test_credentials( instance, helper, username, password )
     if ( loginErrorCode == mssql.LoginErrorType.PasswordMustChange ) then passwordIsGood = true end
     if ( loginErrorCode == mssql.LoginErrorType.AccountLockedOut ) then
       stdnse.debug1("Account %s locked out on %s", username, instance:GetName() )
-      table.insert( instance.ms_sql_empty, string.format("'sa' account is locked out.", result ) )
+      table.insert( instance.ms_sql_empty, "'sa' account is locked out." )
     end
     if ( mssql.LoginErrorMessage[ loginErrorCode ] == nil ) then
       stdnse.debug2("Attemping login to %s: Unknown login error number: %s", instance:GetName(), loginErrorCode )
diff --git a/scripts/p2p-conficker.nse b/scripts/p2p-conficker.nse
index e1358a845..6837a44e4 100644
--- a/scripts/p2p-conficker.nse
+++ b/scripts/p2p-conficker.nse
@@ -605,7 +605,7 @@ action = function(host)
   udp_ports[generated_ports[2]] = true
   udp_ports[generated_ports[4]] = true
 
-  table.insert(response, string.format("Checking for Conficker.C or higher..."))
+  table.insert(response, "Checking for Conficker.C or higher...")
 
   -- Check the TCP ports
   for port in pairs(tcp_ports) do
diff --git a/scripts/rtsp-url-brute.nse b/scripts/rtsp-url-brute.nse
index 37f1d8b8a..8b7c3b1a8 100644
--- a/scripts/rtsp-url-brute.nse
+++ b/scripts/rtsp-url-brute.nse
@@ -115,7 +115,7 @@ action = function(host, port)
 
   local url_iter = urlIterator(f)
   if ( not(url_iter) ) then
-    return stdnse.format_output(false, ("Could not open the URL dictionary: "):format(f))
+    return stdnse.format_output(false, ("Could not open the URL dictionary: %s"):format(f))
   end
 
   local threads = {}
diff --git a/scripts/smb-enum-domains.nse b/scripts/smb-enum-domains.nse
index 9337b1d58..3fd4e4630 100644
--- a/scripts/smb-enum-domains.nse
+++ b/scripts/smb-enum-domains.nse
@@ -84,13 +84,13 @@ action = function(host)
       if(#data.groups > 0) then
         table.insert(piece, string.format("Groups: %s", stdnse.strjoin(", ", data.groups)))
       else
-        table.insert(piece, string.format("Groups: n/a"))
+        table.insert(piece, "Groups: n/a")
       end
 
       if(#data.users > 0) then
         table.insert(piece, string.format("Users: %s", stdnse.strjoin(", ", data.users)))
       else
-        table.insert(piece, string.format("Users: n/a"))
+        table.insert(piece, "Users: n/a")
       end
 
       -- Floor data.max_password_age, if possible
@@ -111,7 +111,7 @@ action = function(host)
       if(data.lockout_threshold) then
         table.insert(piece, string.format("Account lockout: %s attempts in %s minutes will lock out the account for %s minutes", data.lockout_threshold, data.lockout_window or "unlimited", data.lockout_duration or "unlimited"))
       else
-        table.insert(piece, string.format("Account lockout disabled"))
+        table.insert(piece, "Account lockout disabled")
       end
 
       table.insert(response, piece)
diff --git a/scripts/smb-psexec.nse b/scripts/smb-psexec.nse
index aa7f73b64..3d8920380 100644
--- a/scripts/smb-psexec.nse
+++ b/scripts/smb-psexec.nse
@@ -948,7 +948,7 @@ local function get_config(host, config)
         enabled = false
         mod.disabled_message = {}
         table.insert(mod.disabled_message, string.format("Configuration error: Required argument(s) ('%s') weren't given.", stdnse.strjoin("', '", missing_args)))
-        table.insert(mod.disabled_message, string.format("Please add --script-args=[arg]=[value] to your commandline to run this module"))
+        table.insert(mod.disabled_message, "Please add --script-args=[arg]=[value] to your commandline to run this module")
         if(#missing_args == 1) then
           table.insert(mod.disabled_message, string.format("For example: --script-args=%s=123", missing_args[1]))
         else
@@ -1188,7 +1188,7 @@ local function create_service(host, config)
     cleanup(host, config)
 
     if(string.find(err, "MARKED_FOR_DELETE")) then
-      return false, string.format("Service is stuck in 'being deleted' phase on remote machine; try setting script-args=randomseed=abc for now", err)
+      return false, "Service is stuck in 'being deleted' phase on remote machine; try setting script-args=randomseed=abc for now"
     else
       return false, string.format("Couldn't create the service on the remote machine: %s", err)
     end
@@ -1278,7 +1278,7 @@ local function get_output_file(host, config)
         stdnse.debug1("Error in remote service: output file was never created!")
         cleanup(host, config)
 
-        return false, string.format("Error in remote service: output file was never created")
+        return false, "Error in remote service: output file was never created"
       end
 
       stdnse.debug1("Output file %s doesn't exist yet, waiting for %d more seconds", config.output_file, i)