Unintentional file and directory creation with directory traversal in tempfile and tmpdir

There is an unintentional directory creation vulnerability in tmpdir library
bundled with Ruby. And there is also an unintentional file creation
vulnerability in tempfile library bundled with Ruby, because it uses tmpdir
internally

Dir.mktmpdir method introduced by tmpdir library accepts the prefix and the
suffix of the directory which is created as the first parameter. The prefix can
contain relative directory specifiers ../, so this method can be used to
target any directory. So, if a script accepts an external input as the prefix,
and the targeted directory has inappropriate permissions or the ruby process
has inappropriate privileges, the attacker can create a directory or a file at
any directory.

All users running an affected release should upgrade immediately.