CVE-2025-30682

What it actually does

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

Why it matters to the business

Successful exploitation can interrupt database availability for dependent applications and services, causing operational downtime until the server is restarted.

How an attack unfolds

An attacker with low-privileged network credentials connects to the MySQL instance over supported protocols and submits specially crafted queries that exercise the optimizer code path, forcing the server into an unresponsive state.

How to fix it

Upgrade affected MySQL installations to versions later than 8.0.41, 8.4.4, or 9.2.0. Restrict network exposure of the database service and apply vendor-supplied patches as they become available.

How to confirm the fix worked

Verify server version numbers after upgrade, review release notes for optimizer fixes, and perform controlled query tests in a non-production environment to confirm the denial-of-service condition is no longer reproducible.

Typical attack path

1. Obtain low-privileged network access to an affected MySQL instance
2. Establish a connection using one of the supported protocols
3. Transmit crafted queries that reach the vulnerable optimizer logic
4. Trigger repeated crashes or a persistent hang to achieve denial of service

How to detect it

Inspect MySQL error logs and system logs for repeated crash or hang entries, correlate with connection attempts from untrusted sources, and watch for spikes in optimizer-related query patterns.

What your security team should do

• Prioritize patching of internet-facing or high-value MySQL deployments
• Limit database network access to trusted sources only
• Monitor for unexpected server restarts or availability alerts
• Review and tighten user privileges to reduce the attack surface