Univention Corporate Server 4.3 erratum 453 (security)

This update addresses the following issues:
* Stack-buffer overflow in the pgxtovolume function (CVE-2017-17480)
* Integer overflow in opj_j2k_setup_encoder function in openjp2/j2k.c
  (CVE-2018-5785)
* There is excessive iteration in the opj_t1_encode_cblks function of
  openjp2/t1.c. Remote attackers could leverage this vulnerability to cause a
  denial of service via a crafted bmp file. (CVE-2018-6616)
* Division-by-zero vulnerabilities in the functions pi_next_pcrl,
  pi_next_cprl, and pi_next_rpcl in lib/openjp3d/pi.c allow remote attackers
  to cause a denial of service (application crash). (CVE-2018-14423)
* NULL pointer dereference for "red" in the imagetopnm function of
  jp2/convert.c (CVE-2018-18088)