The new systemd vulnerability (CVE-2017-9445) appears to affect the systemd-resolved component, which could allow a remote attacker to crash the systemd daemon by causing a denial of service or run malicious programs on the vulnerable, unpatched machines by using a specially crafted DNS response. To patch the security flaw, Canonical recommends users to update their systems immediately to the new systemd versions that are already available for installation in the stable repositories. Ubuntu 17.04 users need to update to systemd 232-21ubuntu5 and Ubuntu 16.10 users to systemd 231-9ubuntu5.