Debian tmpreaper version 1.6.13+nmu1 has a race condition when doing a
(bind) mount via rename() which could result in local privilege escalation.
Mounting via rename() could potentially lead to a file being placed
elsewhereon the filesystem hierarchy (e.g. /etc/cron.d/) if the directory
being cleaned up was on the same physical filesystem. Fixed versions
include 1.6.13+nmu1+deb9u1 and 1.6.14.

ebarretto

Version on trusty needs the fix, but the fix depends on bind mounts from util-linux package. And the util-linux in trusty doesn't contain that feature. We could use another solution but I am not sure how this might affect the race condition.