# CVE-2026-95845: Moquette unbounded message queue denial of service

Source: https://junglewise.ai/threats/cve-2026-95845-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-95845 · Severity: high · CVSS 7.5 · Published 2026-09-23

Moquette is a lightweight MQTT message broker used to route messages between publishing and subscribing clients. When a fast publisher sends messages to a slow subscriber, messages accumulate without limit in the broker's memory or storage, allowing an attacker to exhaust system resources and crash the broker. This vulnerability affects all versions before 0.18.1.

Technologies: [Moquette](https://junglewise.ai/threats/technologies/moquette), [Moquette-Io Moquette](https://junglewise.ai/threats/technologies/moquette-io-moquette). Vendors: [Moquette](https://junglewise.ai/threats/vendors/moquette), [Moquette-Io](https://junglewise.ai/threats/vendors/moquette-io).

## Quick answers

**Is CVE-2026-95845 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-95845 being exploited in the wild.

**How severe is CVE-2026-95845?** High severity, with a CVSS score of 7.5, published 23 September 2026.

**Which products and versions are affected?** Moquette-Io Moquette before 0.18.1.

**Is there a fix for CVE-2026-95845?** A patch was published on 2026-08-01. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-95845 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-95845?** Check whether you run Moquette or Moquette-Io Moquette at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The broker fails to enforce a maximum length on per-session message queues when a subscriber's in-flight window is full. A remote unauthenticated attacker can send rapid messages to a topic while a slow subscriber remains connected with a full in-flight window, causing unbounded queue accumulation in both memory and persistent storage. The fix introduces a configurable maximum queue depth enforced at the session level.

## Affected products

- Moquette IO Moquette before 0.18.1

## Timeline

- 2026-09-23: disclosed
- 2026-08-01: patched

## References

- [https://github.com/moquette-io/moquette/commit/2482cadfba44e615be704b892009a57ce06a1aba](https://github.com/moquette-io/moquette/commit/2482cadfba44e615be704b892009a57ce06a1aba)
- [https://github.com/moquette-io/moquette/releases/tag/v0.18.1](https://github.com/moquette-io/moquette/releases/tag/v0.18.1)

## Related threats

- [Moquette MQTT broker insecure fallback on authenticator load failure](https://junglewise.ai/threats/cve-2026-95848-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1-when-a)
- [Moquette H2PersistentQueue client ID collision in durable sessions](https://junglewise.ai/threats/cve-2026-95847-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1)
- [Moquette Last-Will authorization bypass](https://junglewise.ai/threats/cve-2026-95846-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1)
- [Moquette MQTT broker stack overflow via deeply nested topics](https://junglewise.ai/threats/cve-2026-95844-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1)
- [Moquette MQTT broker denial of service in shared subscription parsing](https://junglewise.ai/threats/cve-2026-95843-moquette-is-a-lightweight-java-mqtt-broker-prior-to-0-18-1)