CVE-2026-102466: Eclipse Foundation Eclipse Vert.x

High severity, CVSS 8.2. EPSS: 0.3% chance of exploitation in the next 30 days.

In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x MySQL client (vertx-mysql-client) pre-allocates an array for column definitions based on a server-declared column count with no upper-bound validation. A malicious or compromised MySQL server, or an attacker with man-in-the-middle positioning, can send a crafted result set packet with an extremely large column count, causing the client to attempt a massive heap allocation. The resulting OutOfMemoryError crashes the Netty event loop thread, causing a complete denial of service for all connections and verticles in the Vert.x application. The impacted component is io.vertx:vertx-mysql-client.

Affected products

• Eclipse Foundation Eclipse Vert.x: from 4.0.0, up to and including 4.5.34; from 5.0.0, up to and including 5.0.12; from 5.1.0, up to and including 5.1.9; version 5.2.0 only

Published 2026-10-15. Last modified 2026-10-15.