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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
FreeRTOS coreMQTT unaffected
Version Status Constraints
5.0.0 affected —

No data.

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Project Subscriptions

Vendors Products
Freertos Subscribe
Coremqtt Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Fri, 15 May 2026 19:00:00 +0000

Type Values Removed Values Added
Description 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.
Title DoS from MQTT v5.0 Deserialization Fault in core MQTT
First Time appeared Freertos
Freertos coremqtt
Weaknesses CWE-125
CPEs cpe:2.3:a:freertos:coremqtt:5.0.0:*:*:*:*:*:*:*
Vendors & Products Freertos
Freertos coremqtt
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: AMZN

Published:

Updated: 2026-05-15T20:22:58.148Z

Reserved: 2026-05-15T14:25:50.894Z

Link: CVE-2026-8686

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-15T19:17:05.057

Modified: 2026-05-15T19:17:05.057

Link: CVE-2026-8686

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses