Ubuntu Security Notice 6657-2 - USN-6657-1 fixed several vulnerabilities in Dnsmasq. This update provides the corresponding update for Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered that Dnsmasq incorrectly handled validating DNSSEC messages. A remote attacker could possibly use this issue to cause Dnsmasq to consume resources, leading to a denial of service. 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. 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.
