getElementType(XML_Parser parser,
               const ENCODING *enc,
               const char *ptr,
               const char *end)
{
  DTD * const dtd = parser->m_dtd;  /* save one level of indirection */
  const XML_Char *name = poolStoreString(&dtd->pool, enc, ptr, end);
  ELEMENT_TYPE *ret;

  if (!name)
    return NULL;
  ret = (ELEMENT_TYPE *) lookup(parser, &dtd->elementTypes, name, sizeof(ELEMENT_TYPE));
  if (!ret)
    return NULL;
  if (ret->name != name)
    poolDiscard(&dtd->pool);
  else {
    poolFinish(&dtd->pool);
    if (!setElementTypePrefix(parser, ret))
      return NULL;
  }
  return ret;
}

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.