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.
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No vendor fix or workaround currently provided.
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Thu, 15 Oct 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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 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. | |
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| Metrics |
cvssV4_0
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Subscriptions
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Status: PUBLISHED
Assigner: eclipse
Published:
Updated: 2026-10-15T08:26:02.688Z
Reserved: 2026-09-29T08:30:06.333Z
Link: CVE-2026-102464
No data.
Status : Received
Published: 2026-10-15T09:17:15.283
Modified: 2026-10-15T09:17:15.283
Link: CVE-2026-102464
No data.
OpenCVE Enrichment
No data.
No weakness.