diff --git a/src/ray/core_worker/core_worker.cc b/src/ray/core_worker/core_worker.cc
index 877085d8f..fcca76fa6 100644
--- a/src/ray/core_worker/core_worker.cc
+++ b/src/ray/core_worker/core_worker.cc
@@ -426,7 +426,11 @@ CoreWorker::CoreWorker(const CoreWorkerOptions &options, const WorkerID &worker_
       [this](const RayObject &obj) {
         // Run this on the event loop to avoid calling back into the language runtime
         // from the middle of user operations.
-        io_service_.post([this, obj]() { options_.unhandled_exception_handler(obj); });
+        io_service_.post([this, obj]() {
+          if (options_.unhandled_exception_handler != nullptr) {
+            options_.unhandled_exception_handler(obj);
+          }
+        });
       }));
 
   auto check_node_alive_fn = [this](const NodeID &node_id) {