NavigationRequest::CheckLegacyProtocolInSubresource() const {
  if (frame_tree_node_->IsMainFrame())
    return LegacyProtocolInSubresourceCheckResult::ALLOW_REQUEST;

  if (!ShouldTreatURLSchemeAsLegacy(common_params_.url))
    return LegacyProtocolInSubresourceCheckResult::ALLOW_REQUEST;

  FrameTreeNode* parent_ftn = frame_tree_node_->parent();
  DCHECK(parent_ftn);
  const GURL& parent_url = parent_ftn->current_url();
  if (ShouldTreatURLSchemeAsLegacy(parent_url))
    return LegacyProtocolInSubresourceCheckResult::ALLOW_REQUEST;

  RenderFrameHostImpl* parent = parent_ftn->current_frame_host();
  DCHECK(parent);
  const char* console_message =
      "Subresource requests using legacy protocols (like `ftp:`) are blocked. "
      "Please deliver web-accessible resources over modern protocols like "
      "HTTPS. See https://www.chromestatus.com/feature/5709390967472128 for "
      "details.";
  parent->AddMessageToConsole(CONSOLE_MESSAGE_LEVEL_WARNING, console_message);

  return LegacyProtocolInSubresourceCheckResult::BLOCK_REQUEST;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.