by Kastro
Paper/Archive/CVE-2026-8686

CVE-2026-8686

FreeRTOS coreMQTT — DoS from MQTT v5.0 Deserialization Fault in core MQTT

EPSS 0.4%CVSS 9.1
critical.is priorityof 100
34
CVSS 9.1 (NVD)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 32.8.328 × 206.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
coreMQTT5.0.0–CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
AMZN (CNA)8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
AMZN (CNA)7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

advisoryaws.amazon.com/security/security-bulletins/2026-032-awswriteupgithub.com/FreeRTOS/coreMQTT/security/advisories/GHSA-6qh9-r6jp-2wxcpatchgithub.com/FreeRTOS/coreMQTT/releases/tag/v5.0.1