The transit path validation code in Heimdal before 7.3 might allow attackers to bypass the capath policy protection mechanism by leveraging failure to add the previous hop realm to the transit path of issued tickets.
https://github.com/heimdal/heimdal/releases/tag/heimdal-7.3.0
https://github.com/heimdal/heimdal/commit/b1e699103f08d6a0ca46a122193c9da65f6cf837
http://www.h5l.org/advisories.html?show=2017-04-13
http://lists.opensuse.org/opensuse-updates/2017-08/msg00062.html