CVE-2024-20978 is a vulnerability in the Oracle MySQL Server's optimizer component affecting versions 8.0.35 and prior, and 8.2.0 and prior. It allows a high-privileged attacker with network access to cause a denial of service by hanging or crashing the MySQL Server. The vulnerability has a CVSS 3.1 base score of 4.9, indicating a medium severity impact focused on availability.