A Dnsmasq security update has been released for Ubuntu Linux 16.04 LTS.

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Ubuntu Security Notice USN-4924-1
April 22, 2021

dnsmasq vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Dnsmasq.

Software Description:
- dnsmasq: Small caching DNS proxy and DHCP/TFTP server

Details:

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.
(CVE-2017-15107)

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)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 LTS:
dnsmasq 2.75-1ubuntu0.16.04.10
dnsmasq-base 2.75-1ubuntu0.16.04.10
dnsmasq-utils 2.75-1ubuntu0.16.04.10

After a standard system update you need to reboot your computer to make all
the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-4924-1
CVE-2017-15107, CVE-2019-14513

Package Information:
  https://launchpad.net/ubuntu/+source/dnsmasq/2.75-1ubuntu0.16.04.10