Vulnerability-Lookup

GHSA-X5QG-QGV8-Q7CR

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-24 18:32

Details

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.

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

8.3 (High)


                  
                    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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-56111"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-129"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T16:16:32Z",
    "severity": "HIGH"
  },
  "details": "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.",
  "id": "GHSA-x5qg-qgv8-q7cr",
  "modified": "2026-06-24T18:32:40Z",
  "published": "2026-06-24T18:32:40Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56111"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MarlinFirmware/Marlin/issues/28467"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MarlinFirmware/Marlin/pull/28468"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MarlinFirmware/Marlin/commit/1f255d16ec2d456454fd444494cfb338d62b0fa1"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/marlin-firmware-out-of-bounds-write-via-m421-g-code-handler"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-56111 (GCVE-0-2026-56111)

Vulnerability from cvelistv5 – Published: 2026-06-24 14:31 – Updated: 2026-06-24 15:52 X_Open Source

Title

Marlin Firmware 2.1.2.7 Out-of-Bounds Write via M421 G-code Handler

Summary

Severity

8.3 (High)


                        
                          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

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-129 - Improper Validation of Array Index

Assigner

VulnCheck

References

4 references

URL	Tags
https://github.com/MarlinFirmware/Marlin/issues/28467	technical-descriptionexploit
https://github.com/MarlinFirmware/Marlin/pull/28468	issue-tracking
https://github.com/MarlinFirmware/Marlin/commit/1…	patch
https://www.vulncheck.com/advisories/marlin-firmw…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
MarlinFirmware	Marlin	Affected: 0 , ≤ 2.1.2.7 (custom) Unaffected: 1f255d16ec2d456454fd444494cfb338d62b0fa1 (git)

Date Public

2026-06-23 00:00

Credits

Christ Bouchuen

Show details on NVD website

JSON

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

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-X5QG-QGV8-Q7CR

CVE-2026-56111 (GCVE-0-2026-56111)

Tags

Sightings

Nomenclature