Univention Corporate Server 4.2 erratum 457 (security)

This update addresses the following issues:
* allows remote attackers to cause a denial of service (buffer over-read and
  application crash) via a crafted audio file. (CVE-2017-9869)
* allows remote attackers to cause a denial of service (buffer over-read and
  application crash) via a crafted audio file that is mishandled in the code
  for the "block_type == 2" case. (CVE-2017-9870)
* allows remote attackers to cause a denial of service (stack-based buffer
  overflow and application crash) or possibly have unspecified other impact
  via a crafted audio file. (CVE-2017-9871)
* allows remote attackers to cause a denial of service (stack-based buffer
  overflow and application crash) or possibly have unspecified other impact
  via a crafted audio file. (CVE-2017-9872)
* heap-based buffer over-read when handling a malformed file in k_34_4 in
  vbrquantize.c. (CVE-2017-15018)
* heap-based buffer over-read in fill_buffer in libmp3lame/util.c, related to
  lame_encode_buffer_sample_t in libmp3lame/lame.c. (CVE-2017-15045)
* stack-based buffer overflow in unpack_read_samples in frontend/get_audio.c.
  (CVE-2017-15046)