startParsing(XML_Parser parser)
{
    /* hash functions must be initialized before setContext() is called */
    if (parser->m_hash_secret_salt == 0)
      parser->m_hash_secret_salt = generate_hash_secret_salt(parser);
    if (parser->m_ns) {
      /* implicit context only set for root parser, since child
         parsers (i.e. external entity parsers) will inherit it
      */
      return setContext(parser, implicitContext);
    }
    return XML_TRUE;
}

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.