CVE-2025-30684

What it actually does

Flaw in MySQL Server Replication 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 availability is lost until the server is restarted, disrupting dependent applications and services; low EPSS and no KEV status indicate limited immediate widespread risk but still requires prompt attention for production MySQL deployments.

How an attack unfolds

An attacker with high privileges connects over network protocols to a vulnerable MySQL instance and sends specially crafted replication-related requests that exploit the server component, causing it to hang or crash.

How to fix it

Upgrade affected MySQL Server installations to versions beyond 8.0.41, 8.4.4, or 9.2.0 as provided in Oracle's security updates; apply the latest patches for the Replication component.

How to confirm the fix worked

Verify MySQL version numbers post-upgrade and confirm the replication service remains stable under load testing; review Oracle advisory for exact fixed builds.

Typical attack path

1. Obtain high-privileged network credentials for the MySQL server
2. Establish a connection using supported protocols
3. Submit crafted replication traffic targeting the vulnerable component
4. Trigger hang or crash to achieve denial of service

How to detect it

Review MySQL error logs and replication logs for unexpected crashes or hangs coinciding with administrative connections; correlate with network access attempts from privileged accounts.

What your security team should do

• Prioritize patching internet-facing or high-value MySQL instances within standard change windows
• Monitor EPSS trend for any increase indicating rising exploit likelihood
• Restrict network access to MySQL ports to only trusted administrative hosts