What worries me is that 2 months have passed since the vulnerability was fixed and yet there is no new version released which contains the patch... So you're exposed unless you build ZT from source.
zerotier-one (1.6.6) unstable; urgency=medium
* Backport endpoint mitigation against address collision attack.
-- Adam Ierymenko <adam.ierymenko@zerotier.com> Tue, 21 Sep 2021 01:00:00 -0700