static std::string GetMimeType(const std::string& filename) {
  if (base::EndsWith(filename, ".html", base::CompareCase::INSENSITIVE_ASCII)) {
    return "text/html";
  } else if (base::EndsWith(filename, ".css",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "text/css";
  } else if (base::EndsWith(filename, ".js",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "application/javascript";
  } else if (base::EndsWith(filename, ".png",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "image/png";
  } else if (base::EndsWith(filename, ".gif",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "image/gif";
  } else if (base::EndsWith(filename, ".json",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "application/json";
  } else if (base::EndsWith(filename, ".svg",
                            base::CompareCase::INSENSITIVE_ASCII)) {
    return "image/svg+xml";
  }
  LOG(ERROR) << "GetMimeType doesn't know mime type for: "
             << filename
             << " text/plain will be returned";
  return "text/plain";
}

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.