Univention Corporate Server 4.3 erratum 569 (security)

This update addresses the following issue:
* Under certain parameter configurations, when an SMB client accesses a
  network share and the user does not have permission to access the share
  root directory, it is possible for the user to escape from the share
  to see the complete '/' filesystem. Unix permission checks in the kernel
  are still enforced (CVE-2019-10197).