diff --git a/src/core/thread/meshcop_dataset_manager.cpp b/src/core/thread/meshcop_dataset_manager.cpp
index 224e3db88..baf4daff5 100644
--- a/src/core/thread/meshcop_dataset_manager.cpp
+++ b/src/core/thread/meshcop_dataset_manager.cpp
@@ -505,6 +505,7 @@ void DatasetManager::SendSetResponse(const Coap::Header &aRequestHeader, const I
     responseHeader.Finalize();
     SuccessOrExit(error = message->Append(responseHeader.GetBytes(), responseHeader.GetLength()));
 
+    state.Init();
     state.SetState(aState);
     SuccessOrExit(error = message->Append(&state, sizeof(state)));