Univention Corporate Server 4.2 erratum 211 (security)

This update addresses the following issues:
* Crash on receipt of certain malformed DNS requests (CVE-2015-3294)
* Heap-based buffer overflow allows remote attackers to cause a
  denial of service (crash) or execute arbitrary code via a crafted
  DNS response (CVE-2017-14491)
* Heap-based buffer overflow allows remote attackers to cause a
  denial of service (crash) or execute arbitrary code via a crafted
  IPv6 router advertisement request (CVE-2017-14492)
* Stack-based buffer overflow allows remote attackers to cause a
  denial of service (crash) or execute arbitrary code via a
  crafted DHCPv6 request. (CVE-2017-14493)
* When configured as a relay, dnsmasq allows remote attackers to
  obtain sensitive memory information via vectors involving handling
  DHCPv6 forwarded requests (CVE-2017-14494)