==========================================================================
Ubuntu Security Notice USN-6657-1
February 26, 2024

dnsmasq vulnerabilities
==========================================================================

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

- Ubuntu 23.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in Dnsmasq.

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

Details:

Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered
that Dnsmasq icorrectly handled validating DNSSEC messages. A remote
attacker could possibly use this issue to cause Dnsmasq to consume
resources, leading to a denial of service. (CVE-2023-50387)

It was discovered that Dnsmasq incorrectly handled preparing an NSEC3
closest encloser proof. A remote attacker could possibly use this issue to
cause Dnsmasq to consume resources, leading to a denial of service.
(CVE-2023-50868)

It was discovered that Dnsmasq incorrectly set the maximum EDNS.0 UDP
packet size as required by DNS Flag Day 2020. This issue only affected
Ubuntu 23.10. (CVE-2023-28450)

Update instructions:

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

Ubuntu 23.10:
   dnsmasq-base                    2.90-0ubuntu0.23.10.1

Ubuntu 22.04 LTS:
   dnsmasq-base                    2.90-0ubuntu0.22.04.1

Ubuntu 20.04 LTS:
   dnsmasq-base                    2.90-0ubuntu0.20.04.1

This update uses a new upstream release, which includes additional bug
fixes. After a standard system update you need to reboot your computer to
make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-6657-1
   CVE-2023-28450, CVE-2023-50387, CVE-2023-50868

Package Information:
   https://launchpad.net/ubuntu/+source/dnsmasq/2.90-0ubuntu0.23.10.1
   https://launchpad.net/ubuntu/+source/dnsmasq/2.90-0ubuntu0.22.04.1
   https://launchpad.net/ubuntu/+source/dnsmasq/2.90-0ubuntu0.20.04.1