CVE-2024-21057

What it actually does

Flaw in the MySQL Server Optimizer component allows a high-privileged network attacker to trigger a hang or repeatable crash, resulting in complete denial of service.

Why it matters to the business

Database services can be taken offline by authorized insiders or compromised high-privilege accounts, causing operational downtime and potential data access disruption until the server is restarted.

How an attack unfolds

An attacker with high database privileges connects over supported protocols and issues specially crafted queries that exercise a vulnerable code path in the optimizer, causing the server process to hang or crash.

How to fix it

Upgrade affected MySQL Server installations (8.0.35 and earlier) to the latest patched release provided by Oracle. Restrict high-privilege accounts to trusted networks and review query privileges.

How to confirm the fix worked

Confirm the installed MySQL version is newer than 8.0.35, review release notes for the applied patch, and test that the server remains stable under expected query loads from privileged accounts.

Typical attack path

1. Obtain high-privileged database credentials with network access
2. Connect to the MySQL server using any supported protocol
3. Submit crafted optimizer-triggering queries or statements
4. Observe server hang or crash resulting in denial of service

How to detect it

Review database audit logs and process crash dumps for repeated optimizer-related failures or abrupt server terminations initiated by high-privilege sessions; correlate with connection records showing unusual query patterns.

What your security team should do

• Apply the vendor-supplied MySQL update immediately
• Audit and minimize the number of high-privileged database accounts
• Implement network segmentation to limit database access
• Monitor for unusual query patterns from privileged users