diff --git a/libcef/browser/chrome/chrome_content_browser_client_cef.cc b/libcef/browser/chrome/chrome_content_browser_client_cef.cc
index 3a3b06db2..cf28ac9d6 100644
--- a/libcef/browser/chrome/chrome_content_browser_client_cef.cc
+++ b/libcef/browser/chrome/chrome_content_browser_client_cef.cc
@@ -140,6 +140,8 @@ void HandleExternalProtocolHelper(
     const std::optional<url::Origin>& initiating_origin,
     content::WeakDocumentPtr initiator_document,
     const net::IsolationInfo& isolation_info) {
+  CEF_REQUIRE_UIT();
+
   // May return nullptr if frame has been deleted or a cross-document navigation
   // has committed in the same RenderFrameHost.
   auto initiator_rfh = initiator_document.AsRenderFrameHostIfValid();
diff --git a/libcef/browser/net_service/resource_request_handler_wrapper.cc b/libcef/browser/net_service/resource_request_handler_wrapper.cc
index 045f0229a..895cf2c08 100644
--- a/libcef/browser/net_service/resource_request_handler_wrapper.cc
+++ b/libcef/browser/net_service/resource_request_handler_wrapper.cc
@@ -1116,7 +1116,7 @@ class InterceptedRequestHandlerWrapper : public InterceptedRequestHandler {
             init_state_->browser_, init_state_->frame_,
             state->pending_request_.get(), allow_os_execution);
         if (allow_os_execution && init_state_->unhandled_request_callback_) {
-          init_state_->unhandled_request_callback_.Run();
+          CEF_POST_TASK(TID_UI, init_state_->unhandled_request_callback_);
         }
       }
     }