CVE-2026-102464 Denial of service in Eclipse Vert.x
A malicious MQTT broker can cause unbounded memory growth in Vert.x MQTT clients by withholding PUBREL packets, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-102464?
CVE-2026-102464 is a high-severity denial of service vulnerability in Eclipse Vert.x, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-102464?
It affects 1 product.
Products include Eclipse Vert.x.
How do I fix CVE-2026-102464?
No fix has been published for CVE-2026-102464 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-102464 being exploited?
There is no known exploitation of CVE-2026-102464 in the wild and no public exploit code.
Other vulnerabilities in Eclipse Vert.x
- CVE-2019-17640 Path Traversal in Eclipse Vert
- CVE-2018-12542 Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location
- CVE-2018-12544 Moderate severity vulnerability that affects io.vertx:vertx-core
- CVE-2026-102469 Deserialization in Eclipse Vert.x
- CVE-2018-12540 High severity vulnerability that affects io.vertx:vertx-web
Sources
Also known as GHSA-46xj-5735-6qrp, GHSA-g3vx-j9rx-jfm5.