CVE-2026-102464

What it is

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 Eclipse Vert.x MQTT (vertx-mqtt) MqttClient stores every inbound QoS 2 PUBLISH message received from the broker in an internal map (qos2inbound) while awaiting the corresponding PUBREL packet to complete the QoS 2 handshake. This map has no size limit; the maxInflightQueue option is enforced only on the outbound publish path and does not constrain inbound message retention. A malicious or compromised MQTT broker can exploit this by sending QoS 2 PUBLISH messages with distinct packet identifiers and withholding the PUBREL responses. Each incomplete handshake causes the client to retain the full publish message (topic, payload, and metadata) indefinitely, leading to unbounded memory growth in the Vert.x process. This can degrade the MQTT-consuming application or cause out-of-memory termination. The impacted component is io.vertx:vertx-mqtt.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-10-15 09:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-20 19:28 UTC Last updatedMost recent change to the record

Details

Published

2026-10-15 09:17 UTC

Last modified

2026-10-20 19:28 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-770 · Allocation without limits

Record status

Analyzed

Affected

• Eclipse vert.x < 4.5.35
• Eclipse vert.x < 5.1.10
• Eclipse vert.x 5.2.0

Attack profile CVSS 4.0 · 8.2

Attack vector

Network

Complexity

High

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High