CVE-2026-103223: 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 PostgreSQL message decoder reads the 4-byte message length field from the PostgreSQL wire protocol without any maximum validation. A malicious, compromised, or man-in-the-middle PostgreSQL server can send a message header with the length field set to an extremely large value (up to Integer.MAX_VALUE), causing the decoder to accumulate subsequent TCP data into a composite buffer without bound, leading to unbounded memory allocation on the client and an out-of-memory crash. This occurs before authentication completes. The impacted component is io.vertx:vertx-pg-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.