CVE-2026-42209 (GCVE-0-2026-42209)
Vulnerability from cvelistv5 – Published: 2026-05-08 21:40 – Updated: 2026-05-11 15:59
VLAI
EPSS
VEX
Title
FlashMQ: Division by zero crash when using non-default deferred retained message setting
Summary
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.
Severity
6.5 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-11 15:59 UTC
CWE
- CWE-369 - Divide By Zero
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/halfgaar/FlashMQ/security/advi… | x_refsource_CONFIRM |
| https://github.com/halfgaar/FlashMQ/issues/167 | x_refsource_MISC |
| https://github.com/halfgaar/FlashMQ/commit/193b6e… | x_refsource_MISC |
| https://github.com/halfgaar/FlashMQ/releases/tag/… | x_refsource_MISC |
Impacted products
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