A vulnerability in the MySQL Server component 'Optimizer' affects multiple versions including 8.0.40 and prior, 8.4.3 and prior, and 9.1.0 and prior. This flaw allows a low 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 6.5, indicating a medium severity impact focused on availability.