Univention Corporate Server 3.2 erratum 456 (extended maintenance)

Multiple vulnerabilities have been found in libxslt:
* The xsltStylePreCompute function in preproc.c does not check if
  the parent nonfusion" issue. (CVE-2015-7995)
* numbers.c mishandles nssibly have unspecified other impact via a
  crafted document. (CVE-2016-1683)
* numbers.c mishandles t or resource consumption) or possibly have
  unspecified other impact via a crafted document. (CVE-2016-1684)
* heap overread can cause arbitrary code execution or denial of
  service (CVE-2016-4738)
* integer overflow in libxslt (CVE-2017-5029)