diff --git a/third_party/blink/renderer/core/frame/web_frame_widget_impl.cc b/third_party/blink/renderer/core/frame/web_frame_widget_impl.cc
index 1395aa71a377c..c82566ccad845 100644
--- a/third_party/blink/renderer/core/frame/web_frame_widget_impl.cc
+++ b/third_party/blink/renderer/core/frame/web_frame_widget_impl.cc
@@ -1939,6 +1939,12 @@ void WebFrameWidgetImpl::UpdateVisualProperties(
 
   gfx::Size old_visible_viewport_size = widget_base_->VisibleViewportSize();
   ApplyVisualPropertiesSizing(visual_properties);
+  // ApplyVisualPropertiesSizing() may synchronously dispatch JS (the legacy
+  // `orientationchange` event) whose handler can detach this widget's local
+  // root and Close() this WebFrameWidgetImpl, resetting `widget_base_`.
+  if (!widget_base_) {
+    return;
+  }
 
   if (old_visible_viewport_size != widget_base_->VisibleViewportSize()) {
     ForEachLocalFrameControlledByWidget(
@@ -2064,6 +2070,12 @@ void WebFrameWidgetImpl::ApplyVisualPropertiesSizing(
   widget_base_->UpdateSurfaceAndScreenInfo(
       visual_properties.local_surface_id.value_or(viz::LocalSurfaceId()),
       new_compositor_viewport_pixel_rect, visual_properties.screen_infos);
+  // UpdateSurfaceAndScreenInfo() may synchronously dispatch JS (the legacy
+  // `orientationchange` event) whose handler can detach this widget's local
+  // root and Close() this WebFrameWidgetImpl, resetting `widget_base_`.
+  if (!widget_base_) {
+    return;
+  }
 
   // Store this even when auto-resizing, it is the size of the full viewport
   // used for clipping, and this value is propagated down the Widget
diff --git a/third_party/blink/renderer/platform/widget/widget_base.cc b/third_party/blink/renderer/platform/widget/widget_base.cc
index 70a4733201db9..781b2b046b68f 100644
--- a/third_party/blink/renderer/platform/widget/widget_base.cc
+++ b/third_party/blink/renderer/platform/widget/widget_base.cc
@@ -1844,8 +1844,16 @@ void WidgetBase::UpdateSurfaceAndScreenInfo(
         screen_infos_.current().display_color_spaces);
   }
 
-  if (orientation_changed)
+  if (orientation_changed) {
+    // OrientationChanged() may synchronously dispatch the legacy
+    // `orientationchange` DOM event (Android), whose handler can detach this
+    // widget's local-root frame and free `this` via WebFrameWidgetImpl::Close.
+    auto weak_this = weak_ptr_factory_.GetWeakPtr();
     client_->OrientationChanged();
+    if (!weak_this) {
+      return;
+    }
+  }
 
   client_->DidUpdateSurfaceAndScreen(previous_original_screen_infos);
 }