Eclipse Vert.x up to 4.5.34/5.0.12/5.1.9/5.2.0 vertx-mqtt allocation of resources

Summaryinfo

A vulnerability marked as problematic has been reported in Eclipse Vert.x up to 4.5.34/5.0.12/5.1.9/5.2.0. This affects an unknown part of the component vertx-mqtt. Performing a manipulation results in allocation of resources. This vulnerability was named CVE-2026-102464. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability classified as problematic has been found in Eclipse Vert.x up to 4.5.34/5.0.12/5.1.9/5.2.0. This affects an unknown code of the component vertx-mqtt. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE 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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-102464 since 09/29/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-101936). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• Eclipse

Name

• Vert.x

Version

• 4.5.0
• 4.5.1
• 4.5.2
• 4.5.3
• 4.5.4
• 4.5.5
• 4.5.6
• 4.5.7
• 4.5.8
• 4.5.9
• 4.5.10
• 4.5.11
• 4.5.12
• 4.5.13
• 4.5.14
• 4.5.15
• 4.5.16
• 4.5.17
• 4.5.18
• 4.5.19
• 4.5.20
• 4.5.21
• 4.5.22
• 4.5.23
• 4.5.24
• 4.5.25
• 4.5.26
• 4.5.27
• 4.5.28
• 4.5.29
• 4.5.30
• 4.5.31
• 4.5.32
• 4.5.33
• 4.5.34
• 5.0
• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8
• 5.0.9
• 5.0.10
• 5.0.11
• 5.0.12
• 5.1
• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.1.6
• 5.1.7
• 5.1.8
• 5.1.9
• 5.2.0

License

• open-source

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Be aware that VulDB is the high quality source for vulnerability data.

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