Univention Corporate Server 4.2 erratum 348 (security)

This update addresses the following issues:
* mspack/lzxd.c allows remote attackers to cause a denial of service
  (heap-based buffer overflow and application crash) or possibly have
  unspecified other impact via a crafted CHM file. (CVE-2017-6419)
* The cabd_read_string function allows remote attackers to cause a denial of
  service (stack-based buffer over-read and application crash) via a crafted
  CAB file. (CVE-2017-11423)