Ralph Dolmans and Karst Koymans discovered that Unbound did not properly handle certain NSEC records. An attacker could use this to to prove the non-existence (NXDOMAIN answer) of an existing wildcard record, or trick Unbound into accepting a NODATA proof. Updated unbound packages now available for Ubuntu 18.04 LTS, 17.10, 16.04 LTS, and 14.04 LTS  Unbound Security Update for Ubuntu