mplementation had security holes; see
  <http://archives.neohapsis.com/archives/fulldisclosure/2006-11/0344.html>.
  We don't expect that any tar archives in practical use have type 'N'
  records, but if you have one and you trust its contents, you can
  decode it with GNU tar 1.16 or earlier.

* Race conditions have been fixed that in some cases briefly allowed
  files extracted by 'tar -x --same-owner' (or plain 'tar -x', when
  running as root) to be accessed by users that they shouldn't have been.

