CVE-2024-21057 is a vulnerability in Oracle MySQL Server's optimizer component affecting versions 8.0.35 and earlier. It allows a high-privileged attacker with network access to cause a denial of service by hanging or crashing the MySQL Server. The vulnerability impacts availability but does not affect confidentiality or integrity. Oracle has released patches addressing this issue in versions 8.0.36 and later as part of their April 2024 Critical Patch Update.