Google Chrome before 53.0.2785.113 does not ensure that the recipient of a certain IPC message is a valid RenderFrame or RenderWidget, which allows remote attackers to cause a denial of service (invalid pointer dereference and application crash) or possibly have unspecified other impact by leveraging access to a renderer process, related to render_frame_host_impl.cc and render_widget_host_impl.cc, as demonstrated by a Password Manager message.