diff --git a/arangod/Ahuacatl/ahuacatl-codegen.c b/arangod/Ahuacatl/ahuacatl-codegen.c
index f9758f5f9b..0191629a0f 100644
--- a/arangod/Ahuacatl/ahuacatl-codegen.c
+++ b/arangod/Ahuacatl/ahuacatl-codegen.c
@@ -1346,11 +1346,11 @@ static void ProcessValue (TRI_aql_codegen_js_t* const generator,
                           const TRI_aql_node_t* const node) {
   TRI_aql_codegen_scope_t* scope = CurrentScope(generator);
 
-  if (!scope->_buffer) {
+  if (! scope->_buffer) {
     return;
   }
 
-  if (!TRI_ValueJavascriptAql(scope->_buffer, &node->_value, node->_value._type)) {
+  if (! TRI_ValueJavascriptAql(scope->_buffer, &node->_value, node->_value._type)) {
     generator->_errorCode = TRI_ERROR_OUT_OF_MEMORY;
   }
 }
@@ -1401,7 +1401,7 @@ static void ProcessArrayElement (TRI_aql_codegen_js_t* const generator,
                                 const TRI_aql_node_t* const node) {
   TRI_aql_codegen_scope_t* scope = CurrentScope(generator);
 
-  if (!scope->_buffer) {
+  if (! scope->_buffer) {
     return;
   }
 
diff --git a/arangod/Ahuacatl/ahuacatl-conversions.c b/arangod/Ahuacatl/ahuacatl-conversions.c
index b2a0380a05..923e5e6bb6 100644
--- a/arangod/Ahuacatl/ahuacatl-conversions.c
+++ b/arangod/Ahuacatl/ahuacatl-conversions.c
@@ -29,6 +29,7 @@
 
 #include "BasicsC/conversions.h"
 #include "BasicsC/json.h"
+#include "BasicsC/logging.h"
 #include "BasicsC/string-buffer.h"
 #include "BasicsC/strings.h"
 
diff --git a/arangod/Ahuacatl/ahuacatl-optimiser.c b/arangod/Ahuacatl/ahuacatl-optimiser.c
index 83317e7641..d092018084 100644
--- a/arangod/Ahuacatl/ahuacatl-optimiser.c
+++ b/arangod/Ahuacatl/ahuacatl-optimiser.c
@@ -973,7 +973,26 @@ static TRI_aql_node_t* OptimiseUnaryArithmeticOperation (TRI_aql_context_t* cons
   }
   else if (node->_type == TRI_AQL_NODE_OPERATOR_UNARY_MINUS) {
     // - number => eval!
-    node = TRI_CreateNodeValueDoubleAql(context, - TRI_GetNumericNodeValueAql(operand));
+    double value = - TRI_GetNumericNodeValueAql(operand);
+    
+    // check for result validity
+#ifdef isnan
+    if (isnan(value)) {
+      LOG_TRACE("nan value detected after arithmetic optimisation");
+      TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_INVALID_ARITHMETIC_VALUE, NULL);
+      return NULL;
+    }
+#endif
+
+#ifdef isinf
+    if (isinf(value)) {
+      LOG_TRACE("inf value detected after arithmetic optimisation");
+      TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_INVALID_ARITHMETIC_VALUE, NULL);
+      return NULL;
+    }
+#endif
+
+    node = TRI_CreateNodeValueDoubleAql(context, value);
     if (node == NULL) {
       TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
     }
@@ -1230,6 +1249,24 @@ static TRI_aql_node_t* OptimiseBinaryArithmeticOperation (TRI_aql_context_t* con
   else {
     value = 0.0;
   }
+
+  // check for result validity
+
+#ifdef isnan
+  if (isnan(value)) {
+    LOG_TRACE("nan value detected after arithmetic optimisation");
+    TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_INVALID_ARITHMETIC_VALUE, NULL);
+    return NULL;
+  }
+#endif
+
+#ifdef isinf
+  if (isinf(value)) {
+    LOG_TRACE("inf value detected after arithmetic optimisation");
+    TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_INVALID_ARITHMETIC_VALUE, NULL);
+    return NULL;
+  }
+#endif
   
   node = TRI_CreateNodeValueDoubleAql(context, value);
 
diff --git a/js/server/tests/ahuacatl-queries-simple.js b/js/server/tests/ahuacatl-queries-simple.js
index 460d64248c..d7685816ea 100644
--- a/js/server/tests/ahuacatl-queries-simple.js
+++ b/js/server/tests/ahuacatl-queries-simple.js
@@ -752,7 +752,7 @@ function ahuacatlQuerySimpleTestSuite () {
 ////////////////////////////////////////////////////////////////////////////////
 
     testListIndexes: function () {
-      var actual, expected;
+      var actual;
       
       actual = getQueryResults("LET l = [ 1, 2, 3 ] RETURN l[0]");
       assertEqual([ 1 ], actual);
@@ -814,7 +814,7 @@ function ahuacatlQuerySimpleTestSuite () {
 ////////////////////////////////////////////////////////////////////////////////
 
     testNaming: function () {
-      var actual, expected;
+      var actual;
       
       actual = getQueryResults("LET a = [ 1 ] RETURN a[0]");
       assertEqual([ 1 ], actual);
@@ -832,6 +832,14 @@ function ahuacatlQuerySimpleTestSuite () {
       assertEqual([ 1 ], actual);
       
       assertEqual(errors.ERROR_ARANGO_ILLEGAL_NAME.code, getErrorCode(function() { QUERY("LET a = 1 RETURN `a b c`"); } ));
+    },
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief numeric overflow
+////////////////////////////////////////////////////////////////////////////////
+
+    testOverflow: function () {
+      assertEqual(errors.ERROR_QUERY_INVALID_ARITHMETIC_VALUE.code, getErrorCode(function() { QUERY("LET l = 4444444444444555555555555555555555555555555555554444333333333333333333333334444444544 RETURN l * l * l * l"); }));
     }
   };
 }
diff --git a/lib/BasicsC/string-buffer.c b/lib/BasicsC/string-buffer.c
index 40e9a4bac5..34dd4c0f9d 100644
--- a/lib/BasicsC/string-buffer.c
+++ b/lib/BasicsC/string-buffer.c
@@ -876,12 +876,39 @@ int TRI_AppendSizeHexStringBuffer (TRI_string_buffer_t * self, size_t attr) {
 ////////////////////////////////////////////////////////////////////////////////
 
 ////////////////////////////////////////////////////////////////////////////////
-/// @brief appends floating point number with 8 bits
+/// @brief appends floating point number
 ////////////////////////////////////////////////////////////////////////////////
 
 int TRI_AppendDoubleStringBuffer (TRI_string_buffer_t * self, double attr) {
   int res;
 
+// TODO: before activating this check, make it portable
+// isnan and isinf macros are available in posix, and probably in C99 only
+//   // check for NaN
+// #ifdef isnan
+//   if (isnan(attr)) {
+//     res = Reserve(self, 3);
+//     if (res != TRI_ERROR_NO_ERROR) {
+//       return res;
+//     }
+//     TRI_AppendStringStringBuffer(self, "NaN");
+//     return TRI_ERROR_NO_ERROR;
+//   }
+// #endif 
+// 
+//   // check for infinity
+//   // if we do not enforce this check, one of the below loops might never terminate
+// #ifdef isinf
+//   if (isinf(attr)) {
+//     res = Reserve(self, 3);
+//     if (res != TRI_ERROR_NO_ERROR) {
+//       return res;
+//     }
+//     TRI_AppendStringStringBuffer(self, "inf");
+//     return TRI_ERROR_NO_ERROR;
+//   }
+// #endif
+
   res = Reserve(self, 1);
 
   if (res != TRI_ERROR_NO_ERROR) {