Univention Corporate Server 4.4 erratum 140 (security)

This update addresses the following issues:
* slirp: heap buffer overflow while reassembling fragmented datagrams
  (CVE-2018-11806)
* Microarchitectural Store Buffer Data Sampling (MSBDS) (CVE-2018-12126)
* Micro-architectural Load Port Data Sampling - Information Leak (MLPDS)
  (CVE-2018-12127)
* Microarchitectural Fill Buffer Data Sampling (MFBDS) (CVE-2018-12130)
* qemu-guest-agent: Integer overflow causes segmentation fault in
  qmp_guest_file_read() (CVE-2018-12617)
* usb-mtp: path traversal by host filesystem manipulation in Media Transfer
  Protocol (MTP) (CVE-2018-16872)
* rtl8139: integer overflow leads to buffer overflow (CVE-2018-17958)
* lsi53c895a: OOB msg buffer access leads to DoS (CVE-2018-18849)
* ppc64: Out-of-bounds r/w stack access in pnv_lpc_do_eccb (CVE-2018-18954)
* 9pfs: Use-after-free due to race condition while updating fid path
  (CVE-2018-19364)
* 9pfs: crash due to race condition in renaming files (CVE-2018-19489)
* Out-of-bounds read in hw/i2c/i2c-ddc.c allows for memory disclosure
  (CVE-2019-3812)
* slirp: heap buffer overflow in tcp_emu() (CVE-2019-6778)
* Slirp: information leakage in tcp_emu() due to uninitialized stack
  variables (CVE-2019-9824)
* Microarchitectural Data Sampling Uncacheable Memory (MDSUM)
  (CVE-2019-11091)
* qxl: null pointer dereference while releasing spice resources
  (CVE-2019-12155)