CVE-2026-102464
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.