Univention Corporate Server 4.4 erratum 114 (security)

This update addresses the following issues:
* The flv_write_packet function in libavformat/flvenc.c does not check for an
  empty audio packet, leading to an assertion failure. (CVE-2018-15822)
* FFmpeg contains a Buffer Overflow vulnerability in asf_o format demuxer
  that can result in heap-buffer-overflow that may result in remote code
  execution. This attack appears to be exploitable via specially crafted ASF
  file that has to be provided as input to FFmpeg.  (CVE-2018-1999011)
* Denial of service in subtitle decoder allows attackers to hog CPU via
  crafted video file (CVE-2019-9718)
* libavcodec/hevcdec.c mishandles detection of duplicate first slices, which
  allows remote attackers to cause a denial of service (NULL pointer
  dereference and out-of-array access) or possibly have unspecified other
  impact via crafted HEVC data. (CVE-2019-11338)