Ubuntu Security Notice USN-4924-1
April 22, 2021
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 16.04 LTS
Several security issues were fixed in Dnsmasq.
– dnsmasq: Small caching DNS proxy and DHCP/TFTP server
It was discovered that Dnsmasq incorrectly handled certain wildcard
synthesized NSEC records. A remote attacker could possibly use this issue
to prove the non-existence of hostnames that actually exist.
It was discovered that Dnsmasq incorrectly handled certain large DNS
packets. A remote attacker could possibly use this issue to cause Dnsmasq
to crash, resulting in a denial of service. (CVE-2019-14513)
The problem can be corrected by updating your system to the following
Ubuntu 16.04 LTS:
After a standard system update you need to reboot your computer to make all
the necessary changes.