CVE-2025-30688

What it actually does

Low-privileged network attacker can trigger optimizer component flaws in MySQL Server causing repeated hangs or crashes that result in complete denial of service.

Why it matters to the business

Database services become unavailable, interrupting applications and business operations that depend on reliable data access; urgency is moderate given low EPSS and no known exploitation campaigns.

How an attack unfolds

An attacker with valid low-privileged credentials connects over supported protocols and submits crafted queries that exercise vulnerable optimizer paths, forcing the server process into a hang or crash state without requiring authentication bypass or elevated rights.

How to fix it

Upgrade affected MySQL installations to versions beyond 8.0.41, 8.4.4, or 9.2.0 respectively; apply vendor patches for the Server: Optimizer component as soon as available and test in non-production environments first.

How to confirm the fix worked

Confirm patched versions are deployed by running the MySQL version query and monitor for absence of optimizer-related crash signatures after upgrade; re-test connectivity and query workloads to ensure availability is restored.

Typical attack path

1. Obtain low-privileged network credentials for a MySQL instance
2. Establish connection via supported protocols
3. Submit specially crafted queries targeting the optimizer
4. Induce repeated server hangs or crashes to achieve denial of service

How to detect it

Examine MySQL error logs and crash dumps for optimizer component failures, repeated server restarts, or availability loss events; correlate with network connection logs from low-privileged accounts showing unusual query patterns.

• optimizer-related crash in error log
• mysqld process termination with signal 11
• repeated 'hang detected' messages in MySQL logs

What your security team should do

• Prioritize patching all internet-facing or multi-user MySQL deployments within standard change windows
• Review and tighten network access controls for database ports
• Enable enhanced logging of optimizer errors and crashes for ongoing monitoring
• Track EPSS trend for any future increase in exploit likelihood