USN-8457-2: MySQL vulnerabilities

USN-8457-1 fixed several vulnerabilities in MySQL. This update
provides the corresponding fixes for MySQL on Ubuntu 20.04 LTS

Original advisory details:

It was discovered that MySQL Router incorrectly handled repeated TLS
protocol upgrade requests. An unauthenticated remote attacker could
possibly use this issue to cause MySQL Router to crash, resulting in a
denial of service. (CVE-2026-46862)

It was discovered that MySQL Server incorrectly handled connection
authentication. An unauthenticated remote attacker could possibly use this
issue to cause MySQL to crash, resulting in a denial of service.
(CVE-2026-46863)