CVE-2021-41039: Eclipse Mosquitto

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

In versions 1.6 to 2.0.11 of Eclipse Mosquitto, an MQTT v5 client connecting with a large number of user-property properties could cause excessive CPU usage, leading to a loss of performance and possible denial of service.

Affected products

• Eclipse Mosquitto: from 1.6, up to and including 2.0.11

Published 2021-12-01. Last modified 2026-06-17.