diff --git a/common.gypi b/common.gypi
index 0395077e443751..e8b89a76e22487 100644
--- a/common.gypi
+++ b/common.gypi
@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.50',
+    'v8_embedder_string': '-node.51',
 
     ##### V8 defaults for Node.js #####
 
diff --git a/deps/v8/AUTHORS b/deps/v8/AUTHORS
index 6f602e44560bca..13a915c130b7a2 100644
--- a/deps/v8/AUTHORS
+++ b/deps/v8/AUTHORS
@@ -67,6 +67,7 @@ Ben Newman <ben@meteor.com>
 Ben Noordhuis <info@bnoordhuis.nl>
 Benjamin Tan <demoneaux@gmail.com>
 Bert Belder <bertbelder@gmail.com>
+Brendon Tiszka <btiszka@gmail.com>
 Burcu Dogan <burcujdogan@gmail.com>
 Caitlin Potter <caitpotter88@gmail.com>
 Craig Schlenter <craig.schlenter@gmail.com>
diff --git a/deps/v8/src/builtins/builtins-array.cc b/deps/v8/src/builtins/builtins-array.cc
index 3c2fe33c5b4b33..5135f9599b6e2d 100644
--- a/deps/v8/src/builtins/builtins-array.cc
+++ b/deps/v8/src/builtins/builtins-array.cc
@@ -1080,6 +1080,9 @@ bool IterateElements(Isolate* isolate, Handle<JSReceiver> receiver,
     case HOLEY_SEALED_ELEMENTS:
     case HOLEY_NONEXTENSIBLE_ELEMENTS:
     case HOLEY_ELEMENTS: {
+      // Disallow execution so the cached elements won't change mid execution.
+      DisallowJavascriptExecution no_js(isolate);
+
       // Run through the elements FixedArray and use HasElement and GetElement
       // to check the prototype for missing elements.
       Handle<FixedArray> elements(FixedArray::cast(array->elements()), isolate);
@@ -1106,6 +1109,9 @@ bool IterateElements(Isolate* isolate, Handle<JSReceiver> receiver,
     }
     case HOLEY_DOUBLE_ELEMENTS:
     case PACKED_DOUBLE_ELEMENTS: {
+      // Disallow execution so the cached elements won't change mid execution.
+      DisallowJavascriptExecution no_js(isolate);
+
       // Empty array is FixedArray but not FixedDoubleArray.
       if (length == 0) break;
       // Run through the elements FixedArray and use HasElement and GetElement
@@ -1142,6 +1148,9 @@ bool IterateElements(Isolate* isolate, Handle<JSReceiver> receiver,
     }
 
     case DICTIONARY_ELEMENTS: {
+      // Disallow execution so the cached dictionary won't change mid execution.
+      DisallowJavascriptExecution no_js(isolate);
+
       Handle<NumberDictionary> dict(array->element_dictionary(), isolate);
       std::vector<uint32_t> indices;
       indices.reserve(dict->Capacity() / 2);