diff --git a/src/node_env_var.cc b/src/node_env_var.cc
index 40c0515a3dc2e2..02f24fff205ce6 100644
--- a/src/node_env_var.cc
+++ b/src/node_env_var.cc
@@ -47,7 +47,7 @@ class MapKVStore final : public KVStore {
   std::shared_ptr<KVStore> Clone(Isolate* isolate) const override;
 
   MapKVStore() = default;
-  MapKVStore(const MapKVStore& other) : map_(other.map_) {}
+  MapKVStore(const MapKVStore& other) : KVStore(), map_(other.map_) {}
 
  private:
   mutable Mutex mutex_;