CVE-2026-67418 RabbitMQ MQTT 5: inapplicable PUBLISH property disconnects matching subscribers
An authenticated publisher can disconnect matching MQTT subscribers by sending invalid properties, causing a denial of service for those subscribers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-67418?
CVE-2026-67418 is a medium-severity denial of service vulnerability in rabbitmq-server, published on 14 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, the MQTT 5 parser in deps/rabbitmq_mqtt/src/rabbit_mqtt_packet.erl accepts Request-Problem-Information on PUBLISH packets even though the property is valid only for CONNECT. An authenticated publisher with topic write permission can cause the broker to store and route that inapplicable property to a separately authenticated matching subscriber. When the subscriber path serializes the outbound PUBLISH, serialise_prop/2 has no matching clause, and the uncontained function_clause exception closes the victim MQTT or Web MQTT connection. The publisher connection and broker remain available, and queued replay, retained-message persistence, and broker-wide denial of service were not established. This issue is fixed in versions 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5.
Which versions are affected by CVE-2026-67418?
1 open source package ship an affected version, including rabbitmq.
| Package | Affected | Fixed in |
|---|---|---|
rabbitmq Bitnami | From 3.13.0 | 3.13.19, 4.0.24, 4.1.15, 4.2.10, 4.3.5 |
How do I fix CVE-2026-67418?
Upgrade rabbitmq to a fixed version for your release line: 3.13.19, 4.0.24, 4.1.15 or 4.2.10.
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-2026-67418 being exploited?
There is no known exploitation of CVE-2026-67418 in the wild and no public exploit code.
Sources
Also known as AZL-108480, BIT-rabbitmq-2026-67418, DEBIAN-CVE-2026-67418, GHSA-jv99-v328-mvmm, UBUNTU-CVE-2026-67418.