USN-4563-2: NTP vulnerability

USN-4563-2: NTP vulnerability

USN-4563-1 fixed a vulnerability in NTP. This update provides the
corresponding update for Ubuntu 20.04 LTS and Ubuntu 20.10.

Original advisory details:

It was discovered that the fix for CVE-2018-7182 introduced a NULL pointer
dereference into NTP. An attacker could use this vulnerability to cause a
denial of service (crash).
Source: USN-4563-2: NTP vulnerability