FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.26.1, a remote client with retained publish permission can crash the FlashMQ broker when both set_retained_message_defer_timeout and set_retained_message_defer_timeout_spread are configured to non-default values, resulting in denial of service. If anonymous retained publishing is allowed, no authentication is required; otherwise, the attacker needs the corresponding publish permission. This issue has been patched in version 1.26.1.
History

Fri, 08 May 2026 22:00:00 +0000

Type Values Removed Values Added
Description FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.26.1, a remote client with retained publish permission can crash the FlashMQ broker when both set_retained_message_defer_timeout and set_retained_message_defer_timeout_spread are configured to non-default values, resulting in denial of service. If anonymous retained publishing is allowed, no authentication is required; otherwise, the attacker needs the corresponding publish permission. This issue has been patched in version 1.26.1.
Title FlashMQ: Division by zero crash when using non-default deferred retained message setting
Weaknesses CWE-369
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-05-08T21:40:43.284Z

Updated: 2026-05-08T21:40:43.284Z

Reserved: 2026-04-25T05:04:37.028Z

Link: CVE-2026-42209

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-08T22:16:32.103

Modified: 2026-05-08T22:16:32.103

Link: CVE-2026-42209

cve-icon Redhat

No data.