FlashMQ: Division by zero crash when using non-default deferred retained message setting_CVE-2026-42209

{
    "lastseen": "",
    "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.",
    "published": "2026-05-08T21:40:43.284Z",
    "modified": "2026-05-08T21:40:43.284Z",
    "type": "cve",
    "title": "FlashMQ: Division by zero crash when using non-default deferred retained message setting",
    "source": "GitHub_M",
    "references": "https://github.com/halfgaar/FlashMQ/security/advisories/GHSA-2789-vfcg-5922\nhttps://github.com/halfgaar/FlashMQ/issues/167\nhttps://github.com/halfgaar/FlashMQ/commit/193b6e7767889511cfa8e933908ea5e6a1077a1f\nhttps://github.com/halfgaar/FlashMQ/releases/tag/v1.26.1",
    "id": "CVE-2026-42209",
    "bulletinFamily": "",
    "cwe": [
        "CWE-369"
    ],
    "cvelist": null,
    "sourceData": "halfgaar FlashMQ < 1.26.1",
    "sourceHref": "",
    "cvss": {
        "score": 6.5,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
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            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "FlashMQ",
    "version": "< 1.26.1",
    "vendor": "halfgaar",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}