diff --git a/common.gypi b/common.gypi
index 2eb8664697d990..2a82642e350028 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.14',
+    'v8_embedder_string': '-node.15',
 
     ##### V8 defaults for Node.js #####
 
diff --git a/deps/v8/src/heap/cppgc-js/cpp-heap.cc b/deps/v8/src/heap/cppgc-js/cpp-heap.cc
index 712be09f2c3880..8ad35749783bc1 100644
--- a/deps/v8/src/heap/cppgc-js/cpp-heap.cc
+++ b/deps/v8/src/heap/cppgc-js/cpp-heap.cc
@@ -81,7 +81,7 @@ class UnifiedHeapConcurrentMarker
         unified_heap_marking_state_(unified_heap_marking_state) {}
 
   std::unique_ptr<cppgc::Visitor> CreateConcurrentMarkingVisitor(
-      ConcurrentMarkingState&) const final;
+      cppgc::internal::ConcurrentMarkingState&) const final;
 
  private:
   UnifiedHeapMarkingState& unified_heap_marking_state_;
@@ -89,7 +89,7 @@ class UnifiedHeapConcurrentMarker
 
 std::unique_ptr<cppgc::Visitor>
 UnifiedHeapConcurrentMarker::CreateConcurrentMarkingVisitor(
-    ConcurrentMarkingState& marking_state) const {
+    cppgc::internal::ConcurrentMarkingState& marking_state) const {
   return std::make_unique<ConcurrentUnifiedHeapMarkingVisitor>(
       heap(), marking_state, unified_heap_marking_state_);
 }
diff --git a/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.cc b/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.cc
index e235f8885d96f7..16543fe01929fb 100644
--- a/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.cc
+++ b/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.cc
@@ -14,7 +14,7 @@ namespace v8 {
 namespace internal {
 
 UnifiedHeapMarkingVisitorBase::UnifiedHeapMarkingVisitorBase(
-    HeapBase& heap, MarkingStateBase& marking_state,
+    HeapBase& heap, cppgc::internal::MarkingStateBase& marking_state,
     UnifiedHeapMarkingState& unified_heap_marking_state)
     : JSVisitor(cppgc::internal::VisitorFactory::CreateKey()),
       marking_state_(marking_state),
@@ -89,7 +89,7 @@ void MutatorUnifiedHeapMarkingVisitor::VisitWeakRoot(const void* object,
 }
 
 ConcurrentUnifiedHeapMarkingVisitor::ConcurrentUnifiedHeapMarkingVisitor(
-    HeapBase& heap, ConcurrentMarkingState& marking_state,
+    HeapBase& heap, cppgc::internal::ConcurrentMarkingState& marking_state,
     UnifiedHeapMarkingState& unified_heap_marking_state)
     : UnifiedHeapMarkingVisitorBase(heap, marking_state,
                                     unified_heap_marking_state) {}
@@ -99,7 +99,7 @@ bool ConcurrentUnifiedHeapMarkingVisitor::DeferTraceToMutatorThreadIfConcurrent(
     size_t deferred_size) {
   marking_state_.concurrent_marking_bailout_worklist().Push(
       {parameter, callback, deferred_size});
-  static_cast<ConcurrentMarkingState&>(marking_state_)
+  static_cast<cppgc::internal::ConcurrentMarkingState&>(marking_state_)
       .AccountDeferredMarkedBytes(deferred_size);
   return true;
 }
diff --git a/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.h b/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.h
index 05e3affaa804c4..1032a760068cea 100644
--- a/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.h
+++ b/deps/v8/src/heap/cppgc-js/unified-heap-marking-visitor.h
@@ -28,14 +28,12 @@ namespace internal {
 using cppgc::SourceLocation;
 using cppgc::TraceDescriptor;
 using cppgc::WeakCallback;
-using cppgc::internal::ConcurrentMarkingState;
 using cppgc::internal::HeapBase;
-using cppgc::internal::MarkingStateBase;
 using cppgc::internal::MutatorMarkingState;
 
 class V8_EXPORT_PRIVATE UnifiedHeapMarkingVisitorBase : public JSVisitor {
  public:
-  UnifiedHeapMarkingVisitorBase(HeapBase&, MarkingStateBase&,
+  UnifiedHeapMarkingVisitorBase(HeapBase&, cppgc::internal::MarkingStateBase&,
                                 UnifiedHeapMarkingState&);
   ~UnifiedHeapMarkingVisitorBase() override = default;
 
@@ -53,7 +51,7 @@ class V8_EXPORT_PRIVATE UnifiedHeapMarkingVisitorBase : public JSVisitor {
   // JS handling.
   void Visit(const TracedReferenceBase& ref) final;
 
-  MarkingStateBase& marking_state_;
+  cppgc::internal::MarkingStateBase& marking_state_;
   UnifiedHeapMarkingState& unified_heap_marking_state_;
 };
 
@@ -73,7 +71,8 @@ class V8_EXPORT_PRIVATE MutatorUnifiedHeapMarkingVisitor final
 class V8_EXPORT_PRIVATE ConcurrentUnifiedHeapMarkingVisitor final
     : public UnifiedHeapMarkingVisitorBase {
  public:
-  ConcurrentUnifiedHeapMarkingVisitor(HeapBase&, ConcurrentMarkingState&,
+  ConcurrentUnifiedHeapMarkingVisitor(HeapBase&,
+                                      cppgc::internal::ConcurrentMarkingState&,
                                       UnifiedHeapMarkingState&);
   ~ConcurrentUnifiedHeapMarkingVisitor() override = default;