# 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.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Oct 2026
- **Updated:** 14 Oct 2026
- **Also known as:** AZL-108480, BIT-rabbitmq-2026-67418, DEBIAN-CVE-2026-67418, GHSA-jv99-v328-mvmm, UBUNTU-CVE-2026-67418

## 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.

Weakness: CWE-248 (Uncaught Exception), CWE-1286 (Improper Validation of Syntactic Correctness of Input)

## Which versions are affected by CVE-2026-67418?

1 open source package ship an affected version, including rabbitmq.


| Package | Ecosystem | 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.

## Is CVE-2026-67418 being exploited?

There is no known exploitation of CVE-2026-67418 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-67418 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-67418 in the wild and no public exploit code.

Affected packages and fixed versions:
- rabbitmq (Bitnami): affected from 3.13.0; fixed in 3.13.19, 4.0.24, 4.1.15, 4.2.10, 4.3.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-67418/ (Markdown: https://insights.sbomify.com/CVE-2026-67418/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67418
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67418
- OSV: https://osv.dev/vulnerability/CVE-2026-67418

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67418/
Summaries are generated and may contain mistakes; the official description above is the record.