int32_t PPB_URLLoader_Impl::Open(PP_Resource request_id,
                                 scoped_refptr<TrackedCallback> callback) {
  EnterResourceNoLock<PPB_URLRequestInfo_API> enter_request(request_id, true);
  if (enter_request.failed()) {
    Log(PP_LOGLEVEL_ERROR,
        "PPB_URLLoader.Open: invalid request resource ID. (Hint to C++ wrapper"
        " users: use the ResourceRequest constructor that takes an instance or"
        " else the request will be null.)");
    return PP_ERROR_BADARGUMENT;
  }
  return Open(enter_request.object()->GetData(), 0, callback);
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.