Univention Corporate Server 4.2 erratum 386 (security)

This update addresses the following issues:
* OpenJDK-7 was recompiled for UCS-4.2 to fix a package version conflict with
  UCS-4.1.
* CVE-2018-2579: unsynchronized access to encryption key data.
* CVE-2018-2588: LdapLoginModule insufficient username encoding in LDAP
  query.
* CVE-2018-2599: DnsClient missing source port randomization.
* CVE-2018-2602: loading of classes from untrusted locations.
* CVE-2018-2603: DerValue unbounded memory allocation.
* CVE-2018-2618: insufficient strength of key agreement.
* CVE-2018-2629: GSS context use-after-free.
* CVE-2018-2633: LDAPCertStore insecure handling of LDAP referrals.
* CVE-2018-2634: use of global credentials for HTTP/SPNEGO.
* CVE-2018-2637: SingleEntryRegistry incorrect setup of deserialization
  filter.
* CVE-2018-2641: GTK library loading use-after-free.
* CVE-2018-2663: ArrayBlockingQueue deserialization to an inconsistent state.
* CVE-2018-2677: unbounded memory allocation during deserialization.
* CVE-2018-2678: unbounded memory allocation in BasicAttributes
  deserialization.