CVE-2025-30683

What it actually does

High-privileged network attacker can trigger a hang or repeatable crash in the MySQL Server replication component, resulting in complete denial of service.

Why it matters to the business

Database servers become unavailable, causing application outages and potential data access disruption until the service is restarted.

How an attack unfolds

An attacker with high privileges and network access to an affected MySQL instance sends specially crafted replication protocol messages that exploit a flaw in the server replication handling, leading to a hang or crash.

How to fix it

Upgrade affected MySQL Server installations to versions later than 8.0.41, 8.4.4, or 9.2.0 as appropriate for the release line. Apply vendor patches promptly given the published date and EPSS trend.

How to confirm the fix worked

Verify MySQL version after upgrade, confirm replication functionality remains operational, and test that crafted replication traffic no longer causes crashes.

Typical attack path

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

How to detect it

Review MySQL error logs and replication logs for unexpected crashes or hang events around replication protocol handling; correlate with privileged account activity on replication ports.

What your security team should do

• Prioritize patching MySQL Server instances exposed to network replication traffic
• Review and restrict high-privileged replication accounts to least privilege
• Monitor EPSS score trajectory and apply updates before any increase in exploit maturity
• Test replication failover and recovery procedures in staging environments