Univention Corporate Server 4.2 erratum 577 (extended maintenance)

This update addresses the following issues:
* CVE-2017-9993: Libav does not properly restrict HTTP Live Streaming
  filename extensions and demuxer names, which allows attackers to read
  arbitrary files via crafted playlist data.
* CVE-2017-9994: libavcodec/webp.c in Libav before does not ensure that
  pix_fmt is set, which allows remote attackers to cause a denial of service
  unspecified other impact via a crafted file, related to the
  vp8_decode_mb_row_no_filter and pred8x8_128_dc_8_c functions.
* CVE-2017-14055: a DoS in mv_read_header() due to lack of an end-of-file
  check might cause huge CPU and memory consumption.
* CVE-2017-14056: a DoS in rl2_read_header() due to lack of an end-of-file
  check might cause huge CPU consumption.
* CVE-2017-14057: a DoS in asf_read_marker() due to lack of an end-of-file
  check might cause huge CPU and memory consumption.
* CVE-2017-14170: a DoS in mxf_read_index_entry_array() due to lack of an
  end-of-file check might cause huge CPU consumption.
* CVE-2017-14171: a DoS in nsv_parse_NSVf_header() due to lack of an
  end-of-file check might cause huge CPU consumption.
* CVE-2017-14767: The sdp_parse_fmtp_config_h264 function in
  libavformat/rtpdec_h264.c mishandles empty sprop-parameter-sets values,
  which allows remote attackers to cause a denial of service (heap buffer
  overflow) or possibly have unspecified other impact via a crafted sdp file.
* CVE-2017-15672: The read_header function in libavcodec/ffv1dec.c allows
  remote attackers to have unspecified impact via a crafted MP4 file, which
  triggers an out-of-bounds read.
* CVE-2017-17130: The ff_free_picture_tables function in
  libavcodec/mpegpicture.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 file, related to
  vc1_decode_i_blocks_adv.
* CVE-2018-6621: The decode_frame function in libavcodec/utvideodec.c in
  Libav allows remote attackers to cause a denial of service (out of array
  read) via a crafted AVI file.
* CVE-2018-7557: The decode_init function in libavcodec/utvideodec.c in Libav
  allows remote attackers to cause a denial of service (out of array read)
  via an AVI file with crafted dimensions within chroma subsampling data.
* CVE-2018-14394: libavformat/movenc.c in Libav allows attackers to cause a
  denial of service (application crash caused by a divide-by-zero error) with
  a user crafted Waveform audio file.
* CVE-2018-1999010: Libav contains multiple out of array access
  vulnerabilities in the mms protocol that can result in attackers accessing
  out of bound data.