CVE-2025-30681

What it actually does

High-privileged network attacker can trigger a partial denial of service against the replication component of affected MySQL Server versions.

Why it matters to the business

Brief database availability loss for authorized administrators may interrupt replication-dependent operations and require manual intervention.

How an attack unfolds

An attacker who already possesses high-privileged network credentials connects via supported protocols and sends specially crafted replication traffic that crashes or stalls the server process.

How to fix it

Upgrade MySQL Server to a fixed release; for the listed nginx packages on Ubuntu apply 1.18.0-0ubuntu1.6 (20.04) or 1.18.0-6ubuntu14.5 (22.04) where applicable.

How to confirm the fix worked

Verify running version numbers against the fixed releases and confirm the replication component no longer accepts the triggering input without crashing.

Typical attack path

1. Obtain high-privileged database credentials
2. Establish network connectivity to the MySQL instance
3. Issue malicious replication commands or packets
4. Trigger partial service interruption

How to detect it

Review MySQL error logs and replication thread crash dumps around the time of suspected issues; correlate with privileged login events from untrusted sources.

What your security team should do

• Apply the listed package updates immediately on all affected Ubuntu systems
• Restrict network access to MySQL ports to only trusted administrative hosts
• Monitor EPSS trend and re-assess if exploit code appears