diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index 8ee7f93f5cf..7af43cf2cda 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -2948,6 +2948,7 @@ bool Viewport::_sub_windows_forward_input(const Ref<InputEvent> &p_event) {
 void Viewport::push_input(const Ref<InputEvent> &p_event, bool p_local_coords) {
 	ERR_MAIN_THREAD_GUARD;
 	ERR_FAIL_COND(!is_inside_tree());
+	ERR_FAIL_COND(p_event.is_null());
 
 	if (disable_input) {
 		return;