static VALUE read_memory(VALUE klass, VALUE content)
{
  xmlSchemaPtr schema;
  xmlSchemaParserCtxtPtr ctx = xmlSchemaNewMemParserCtxt(
      (const char *)StringValuePtr(content),
      (int)RSTRING_LEN(content)
  );
  VALUE rb_schema;
  VALUE errors = rb_ary_new();
  xmlSetStructuredErrorFunc((void *)errors, Nokogiri_error_array_pusher);

#ifdef HAVE_XMLSCHEMASETPARSERSTRUCTUREDERRORS
  xmlSchemaSetParserStructuredErrors(
    ctx,
    Nokogiri_error_array_pusher,
    (void *)errors
  );
#endif

   schema = xmlSchemaParse(ctx);

  xmlSetStructuredErrorFunc(NULL, NULL);
  xmlSchemaFreeParserCtxt(ctx);

  if(NULL == schema) {
    xmlErrorPtr error = xmlGetLastError();
    if(error)
      Nokogiri_error_raise(NULL, error);
    else
      rb_raise(rb_eRuntimeError, "Could not parse document");

    return Qnil;
  }

  rb_schema = Data_Wrap_Struct(klass, 0, dealloc, schema);
  rb_iv_set(rb_schema, "@errors", errors);

  return rb_schema;
}
The software 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.