NanoMQ $share/ Subscription Validation and Forwarding Parsing Inconsistency: NULL Pointer Increment Causes Crash_CVE-2025-68699

{
    "lastseen": "",
    "description": "NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In version 0.24.6, NanoMQ has a protocol parsing / forwarding inconsistency when handling shared subscriptions ($share/). A malformed SUBSCRIBE topic such as $share/ab (missing the second /) is not strictly validated during the subscription stage, so the invalid Topic Filter is stored into the subscription table. Later, when any PUBLISH matches this subscription, the broker send path (nmq_pipe_send_start_v4/v5) performs a second $share/ parsing using strchr() and increments the returned pointer without NULL checks. If the second strchr() returns NULL, sub_topic++ turns the pointer into an invalid address (e.g. 0x1). This invalid pointer is then passed into topic_filtern(), which triggers strlen() and crashes with SIGSEGV. The crash is stable and remotely triggerable. This issue has been patched in version 0.24.7.",
    "published": "2026-02-04T19:25:12.716Z",
    "modified": "2026-02-04T19:51:10.769Z",
    "type": "cve",
    "title": "NanoMQ $share/ Subscription Validation and Forwarding Parsing Inconsistency: NULL Pointer Increment Causes Crash",
    "source": "GitHub_M",
    "references": "https://github.com/nanomq/nanomq/security/advisories/GHSA-qv5f-c6v2-2f8h\nhttps://github.com/nanomq/nanomq/commit/89d68d678e7f841ae7baa45cba8d9bc7ddc9ef4b",
    "id": "CVE-2025-68699",
    "bulletinFamily": "",
    "cwe": [
        "CWE-476"
    ],
    "cvelist": null,
    "sourceData": "nanomq nanomq = 0.24.6",
    "sourceHref": "",
    "cvss": {
        "score": 6.5,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "nanomq",
    "version": "= 0.24.6",
    "vendor": "nanomq",
    "ai_description": "",
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    "ai_score": 0
}