# CVE-2026-57227: Suricata MQTT parser resource exhaustion in transaction handling

Source: https://junglewise.ai/threats/cve-2026-57227-suricata-is-a-network-intrusion-detection-system-intrusion  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-57227 · Severity: high · CVSS 7.5 · Published 2026-09-18

Suricata is a network intrusion detection and prevention system that monitors and analyzes traffic. An attacker sending crafted MQTT protocol messages can cause the MQTT parser to accumulate unbounded transaction state, exhausting CPU and memory resources and leading to system slowdown or denial of service.

Technologies: [OISF Suricata](https://junglewise.ai/threats/technologies/suricata). Vendors: [OISF](https://junglewise.ai/threats/vendors/oisf).

## Quick answers

**Is CVE-2026-57227 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57227 being exploited in the wild.

**How severe is CVE-2026-57227?** High severity, with a CVSS score of 7.5, published 18 September 2026.

**Which products and versions are affected?** OISF Suricata 7.0.0 until 7.0.17 and 8.0.0 until 8.0.6.

**Is there a fix for CVE-2026-57227?** A patch was published on 2026-09-18: Fixed in versions 7.0.17 and 8.0.6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57227 attacked?** It is in a hosted service.

**Am I affected by CVE-2026-57227?** Check whether you run OISF Suricata 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 MQTT parser in rust/src/mqtt/mqtt.rs fails to enforce a limit on repeated PUBREC or PUBREL messages within a single transaction, allowing an attacker to append these messages indefinitely. This resource exhaustion occurs when processing network traffic without authentication or user interaction required. The vulnerability is resolved by bounding the number of messages per transaction.

## Affected products

- OISF Suricata 7.0.0 until 7.0.17 and 8.0.0 until 8.0.6

## Timeline

- 2026-09-18: disclosed
- 2026-09-18: patched: Fixed in versions 7.0.17 and 8.0.6

## References

- [https://github.com/OISF/suricata/commit/03ba8a71d827dd36a0ceb512f45d2f440f260a3a](https://github.com/OISF/suricata/commit/03ba8a71d827dd36a0ceb512f45d2f440f260a3a)
- [https://github.com/OISF/suricata/commit/5cde93dea38533c9b225128ba9d54955997dc273](https://github.com/OISF/suricata/commit/5cde93dea38533c9b225128ba9d54955997dc273)

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