{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-56111",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-06-18T19:15:10.650Z",
        "datePublished": "2026-06-24T14:31:04.284Z",
        "dateUpdated": "2026-07-28T01:49:41.086Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
                "shortName": "VulnCheck",
                "dateUpdated": "2026-07-28T01:49:41.086Z"
            },
            "title": "Marlin Firmware 2.1.2.7 Out-of-Bounds Write via M421 G-code Handler",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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."
                }
            ],
            "tags": [
                "x_open-source"
            ],
            "datePublic": "2026-06-23T00:00:00.000Z",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "cweId": "CWE-129",
                            "description": "Improper Validation of Array Index",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "defaultStatus": "affected",
                    "packageURL": "pkg:github/MarlinFirmware/Marlin",
                    "vendor": "MarlinFirmware",
                    "product": "Marlin",
                    "repo": "https://github.com/MarlinFirmware/Marlin",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "0",
                            "versionType": "custom",
                            "lessThanOrEqual": "2.1.2.7"
                        },
                        {
                            "status": "unaffected",
                            "version": "1f255d16ec2d456454fd444494cfb338d62b0fa1",
                            "versionType": "git"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:marlinfw:marlin_firmware:*:*:*:*:*:*:*:*",
                                    "versionEndIncluding": "2.1.2.7"
                                }
                            ]
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "HIGH",
                        "subIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "HIGH",
                        "subAvailabilityImpact": "NONE",
                        "exploitMaturity": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "valueDensity": "NOT_DEFINED",
                        "vulnerabilityResponseEffort": "NOT_DEFINED",
                        "providerUrgency": "NOT_DEFINED",
                        "version": "4.0",
                        "baseSeverity": "HIGH",
                        "baseScore": 8.3,
                        "vectorString": "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"
                    }
                },
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV3_1": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "HIGH",
                        "availabilityImpact": "HIGH",
                        "version": "3.1",
                        "baseSeverity": "CRITICAL",
                        "baseScore": 9.1,
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
                    }
                }
            ],
            "references": [
                {
                    "url": "https://github.com/MarlinFirmware/Marlin/issues/28467",
                    "name": "Researcher Disclosure",
                    "tags": [
                        "technical-description",
                        "exploit"
                    ]
                },
                {
                    "url": "https://github.com/MarlinFirmware/Marlin/pull/28468",
                    "name": "Pull Request",
                    "tags": [
                        "issue-tracking"
                    ]
                },
                {
                    "url": "https://github.com/MarlinFirmware/Marlin/commit/1f255d16ec2d456454fd444494cfb338d62b0fa1",
                    "name": "Patch Commit",
                    "tags": [
                        "patch"
                    ]
                },
                {
                    "url": "https://www.vulncheck.com/advisories/marlin-firmware-out-of-bounds-write-via-m421-g-code-handler",
                    "tags": [
                        "third-party-advisory"
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Christ Bouchuen",
                    "type": "finder"
                }
            ],
            "source": {
                "discovery": "UNKNOWN"
            },
            "x_generator": {
                "engine": "vulncheck"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-06-24T15:52:16.839509Z",
                                "id": "CVE-2026-56111",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-06-24T15:52:56.140Z"
                }
            }
        ]
    }
}