bind9 vulnerabilities

USN-6909-1 fixed several vulnerabilities in Bind. This update provides
the corresponding update for Ubuntu 18.04 LTS.

Original advisory details:

Toshifumi Sakaguchi discovered that Bind incorrectly handled having a very
large number of RRs existing at the same time. A remote attacker could
possibly use this issue to cause Bind to consume resources, leading to a
denial of service. (CVE-2024-1737)

It was discovered that Bind incorrectly handled a large number of SIG(0)
signed requests. A remote attacker could possibly use this issue to cause
Bind to consume resources, leading to a denial of service. (CVE-2024-1975)