GitLab

  tok = find_by_keyword(tokens, K_NETWORK_STATUS_VERSION);
  tor_assert(tok);
  if (tok->n_args > 1) {
    int flavor = networkstatus_parse_flavor_name(tok->args[1]);
    if (flavor < 0) {
      log_warn(LD_DIR, "Can't parse document with unknown flavor %s",
               escaped(tok->args[2]));
      goto err;
    }
    ns->flavor = flav = flavor;
  }

networkstatus_parse_vote_from_string() validates the second argument of network-status-version which is the flavor of the consensus. If the flavor is invalid it log_warn()s the third argument which is not guaranteed to exist. This means that escaped() receives a non-allocated section of memory as its argument and treats it as a pointer to a string; this should lead to a segfault.