CVE-2026-102466

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-15 · updated 2026-10-20
Weakness: CWE-789

Description

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 4.5.0 before 4.5.35; from 5.0.0 before 5.1.10; 5.2.0 — fixed in 4.5.35, 5.1.10

How to fix

Upgrade to a fixed version: Eclipse Foundation Eclipse Vert.x 4.5.35, 5.1.10. Check the vendor advisory for mitigations.

References

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