CVE-2026-8686DoS from MQTT v5.0 Deserialization Fault in core MQTT

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/FreeRTOS/coreMQTT/releases/tag/v5.0.1 patchRelease Notes
• https://aws.amazon.com/security/security-bulletins/2026-032-aws/ vendor-advisoryVendor Advisory
• https://github.com/FreeRTOS/coreMQTT/security/advisories/GHSA-6qh9-r6jp-2wxc third-party-advisoryVendor Advisory