CVE-2019-11778: Eclipse Mosquitto

Medium severity, CVSS 5.4. EPSS: 0.8% chance of exploitation in the next 30 days.

If an MQTT v5 client connects to Eclipse Mosquitto versions 1.6.0 to 1.6.4 inclusive, sets a last will and testament, sets a will delay interval, sets a session expiry interval, and the will delay interval is set longer than the session expiry interval, then a use after free error occurs, which has the potential to cause a crash in some situations.

Affected products

• Eclipse Mosquitto: from 1.6, before 1.6.5 (fixed in 1.6.5)

Published 2019-09-18. Last modified 2026-06-17.