Univention Corporate Server 4.2 erratum 375 (security)

This update addresses the following issue:
* An exploitable heap overflow vulnerability exists in the
  gdk_pixbuf__jpeg_image_load_increment functionality. A specially crafted
  jpeg file can cause a heap overflow resulting in remote code execution. An
  attacker can send a file or url to trigger this vulnerability.
  (CVE-2017-2862)
* Several integer overflow issues in the gif_get_lzw function resulting in
  memory corruption and potential code execution (CVE-2017-1000422)