void nntp_bcache_update(struct NntpData *nntp_data)
{
  mutt_bcache_list(nntp_data->bcache, nntp_bcache_delete, nntp_data);
}

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.