diff --git a/src/node_env_var.cc b/src/node_env_var.cc
index 6eb47a4cecbf91..c80efbd7536bc8 100644
--- a/src/node_env_var.cc
+++ b/src/node_env_var.cc
@@ -45,7 +45,7 @@ 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_;