Marlin Firmware 2.1.2.7 Out-of-Bounds Write via M421 G-code Handler_CVE-2026-56111

{
    "lastseen": "",
    "description": "Marlin Firmware through 2.1.2.7, fixed in commit 1f255d1, when built with MESH_BED_LEVELING enabled, contains an out-of-bounds write vulnerability in the M421 G-code handler that allows attackers to corrupt firmware memory by supplying out-of-range X and Y grid indices. Attackers can send a single crafted G-code command via USB serial, network interface, or malicious gcode file to write an attacker-controlled 32-bit float value past the z_values array bounds, corrupting adjacent firmware variables and causing denial of service or firmware state corruption.",
    "published": "2026-06-24T14:31:04.284Z",
    "modified": "2026-06-24T14:31:04.284Z",
    "type": "cve",
    "title": "Marlin Firmware 2.1.2.7 Out-of-Bounds Write via M421 G-code Handler",
    "source": "VulnCheck",
    "references": "https://github.com/MarlinFirmware/Marlin/issues/28467\nhttps://github.com/MarlinFirmware/Marlin/pull/28468\nhttps://github.com/MarlinFirmware/Marlin/commit/1f255d16ec2d456454fd444494cfb338d62b0fa1\nhttps://www.vulncheck.com/advisories/marlin-firmware-out-of-bounds-write-via-m421-g-code-handler",
    "id": "CVE-2026-56111",
    "bulletinFamily": "",
    "cwe": [
        "CWE-129"
    ],
    "cvelist": null,
    "sourceData": "MarlinFirmware Marlin 0",
    "sourceHref": "",
    "cvss": {
        "score": 8.3,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Marlin",
    "version": "0",
    "vendor": "MarlinFirmware",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}