CVE-2026-8686

HIGH 7.5

DoS from MQTT v5.0 Deserialization Fault in core MQTT

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

Missing bounds validation in the MQTT v5.0 property parser in coreMQTT before 5.0.1 allows an MQTT broker to cause a denial of service by sending a crafted packet. To remediate this issue, users should upgrade to v5.0.1.

CWE	CWE-125
Vendor	freertos
Product	coremqtt
Published	May 15, 2026
Last Updated	May 15, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

FreeRTOS / coreMQTT

5.0.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/FreeRTOS/coreMQTT/releases/tag/v5.0.1 aws.amazon.com: https://aws.amazon.com/security/security-bulletins/2026-032-aws/ github.com: https://github.com/FreeRTOS/coreMQTT/security/advisories/GHSA-6qh9-r6jp-2wxc

Credits

Epsilon