diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index 61b80c622a809e..a0618675872aac 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -98,7 +98,7 @@ Local<Object> New(Isolate* isolate, Handle<String> string, enum encoding enc) {
 
   size_t length = StringBytes::Size(isolate, string, enc);
 
-  Local<Object> buf = New(length);
+  Local<Object> buf = New(isolate, length);
   char* data = Buffer::Data(buf);
   StringBytes::Write(isolate, data, length, string, enc);
 
diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index b6cb4f10e5698f..04b50361bab264 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -4593,7 +4593,7 @@ void RandomBytesCheck(RandomBytesRequest* req, Local<Value> argv[2]) {
     size_t size;
     req->return_memory(&data, &size);
     argv[0] = Null(req->env()->isolate());
-    argv[1] = Buffer::Use(data, size);
+    argv[1] = Buffer::Use(req->env()->isolate(), data, size);
   }
 }
 
diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index b014bae40dffc9..901a4a001df051 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -165,9 +165,9 @@ void SyncProcessStdioPipe::Close() {
 }
 
 
-Local<Object> SyncProcessStdioPipe::GetOutputAsBuffer() const {
+Local<Object> SyncProcessStdioPipe::GetOutputAsBuffer(Isolate* isolate) const {
   size_t length = OutputLength();
-  Local<Object> js_buffer = Buffer::New(length);
+  Local<Object> js_buffer = Buffer::New(isolate, length);
   CopyOutput(Buffer::Data(js_buffer));
   return js_buffer;
 }
@@ -679,7 +679,7 @@ Local<Array> SyncProcessRunner::BuildOutputArray() {
   for (uint32_t i = 0; i < stdio_count_; i++) {
     SyncProcessStdioPipe* h = stdio_pipes_[i];
     if (h != nullptr && h->writable())
-      js_output->Set(i, h->GetOutputAsBuffer());
+      js_output->Set(i, h->GetOutputAsBuffer(env()->isolate()));
     else
       js_output->Set(i, Null(env()->isolate()));
   }
diff --git a/src/spawn_sync.h b/src/spawn_sync.h
index 4a71b75202b5b2..9a544fa0576402 100644
--- a/src/spawn_sync.h
+++ b/src/spawn_sync.h
@@ -72,7 +72,7 @@ class SyncProcessStdioPipe {
   int Start();
   void Close();
 
-  Local<Object> GetOutputAsBuffer() const;
+  Local<Object> GetOutputAsBuffer(Isolate* isolate) const;
 
   inline bool readable() const;
   inline bool writable() const;
diff --git a/src/util.cc b/src/util.cc
index f382b3d565a8cf..a793368c2cdfa8 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -13,7 +13,7 @@ Utf8Value::Utf8Value(v8::Isolate* isolate, v8::Handle<v8::Value> value)
     return;
 
   // Allocate enough space to include the null terminator
-  size_t len = StringBytes::StorageSize(string, UTF8) + 1;
+  size_t len = StringBytes::StorageSize(isolate, string, UTF8) + 1;
   if (len > sizeof(str_st_)) {
     str_ = static_cast<char*>(malloc(len));
     CHECK_NE(str_, nullptr);