diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.cc b/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.cc
index d341b84886578..9a8d63a4eb8d7 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.cc
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.cc
@@ -38,6 +38,11 @@ using ::ui::mojom::DragOperation;
 // the global XdndSelection mid-drag. Mirrors desktop_drag_drop_client_win.cc.
 bool g_is_dragging = false;
 
+// Set by DesktopWindowTreeHostPlatform::RunMoveLoop. The window-move (tab-drag)
+// path enters X11WholeScreenMoveLoop::RunMoveLoop without going through
+// StartDragAndDrop, so g_is_dragging alone does not cover it.
+bool g_window_move_in_progress = false;
+
 // The minimum alpha required so we would treat the pixel as visible.
 constexpr uint32_t kMinAlpha = 32;
 
@@ -133,6 +138,12 @@ DesktopDragDropClientOzone::DesktopDragDropClientOzone(
     ui::WmDragHandler* drag_handler)
     : root_window_(root_window), drag_handler_(drag_handler) {}
 
+// static
+base::AutoReset<bool>
+DesktopDragDropClientOzone::ScopedSuppressForWindowMove() {
+  return base::AutoReset<bool>(&g_window_move_in_progress, true);
+}
+
 DesktopDragDropClientOzone::~DesktopDragDropClientOzone() {
   ResetDragDropTarget();
   observers_.Notify(
@@ -152,7 +163,7 @@ DragOperation DesktopDragDropClientOzone::StartDragAndDrop(
 
   // A renderer can send LocalFrameHost::StartDragging at any time, so reject
   // (rather than CHECK) re-entrant drags from a second top-level window.
-  if (g_is_dragging) {
+  if (g_is_dragging || g_window_move_in_progress) {
     return DragOperation::kNone;
   }
   base::AutoReset<bool> drag_scoper(&g_is_dragging, true);
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.h b/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.h
index 5a14b467d43a6..b46de97a92f8f 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.h
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/auto_reset.h"
 #include "base/functional/callback.h"
 #include "base/memory/raw_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ -50,6 +51,11 @@ class VIEWS_EXPORT DesktopDragDropClientOzone
 
   ~DesktopDragDropClientOzone() override;
 
+  // Called by the window-move (tab-drag) entry point so that a
+  // renderer-initiated data drag cannot start inside the window-move's nested
+  // kNestableTasksAllowed RunLoop. See StartDragAndDrop.
+  [[nodiscard]] static base::AutoReset<bool> ScopedSuppressForWindowMove();
+
  protected:
   friend class DesktopDragDropClientOzoneTest;
 
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_platform.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_platform.cc
index b958f491aefad..4a284a525e0ba 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_platform.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_platform.cc
@@ -766,6 +766,11 @@ Widget::MoveLoopResult DesktopWindowTreeHostPlatform::RunMoveLoop(
     const gfx::Vector2d& drag_offset,
     Widget::MoveLoopSource source,
     Widget::MoveLoopEscapeBehavior escape_behavior) {
+  // The window-move loop runs a kNestableTasksAllowed RunLoop that pumps Mojo
+  // IPC; suppress renderer-initiated data drags for its duration so a
+  // compromised renderer in another window cannot hijack the user's gesture.
+  auto suppress_data_drag =
+      DesktopDragDropClientOzone::ScopedSuppressForWindowMove();
   auto* move_loop_handler = ui::GetWmMoveLoopHandler(*platform_window());
   if (move_loop_handler && move_loop_handler->RunMoveLoop(drag_offset)) {
     return Widget::MoveLoopResult::kSuccessful;