CVE-2026-8686 — HIGH (7.5) — White Hats Nepal

Vulnerability 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.

CVSS Score

7.5

HIGH

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 Products

Vendor	Product	Versions
Freertos	Coremqtt	5.0.0

Related Weaknesses (CWE)

CWE-125

References

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

FAQ

What is CVE-2026-8686?

CVE-2026-8686 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 sh...

How severe is CVE-2026-8686?

CVE-2026-8686 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-8686?

Check the references section above for vendor advisories and patch information. Affected products include: Freertos Coremqtt.