FKIE_CVE-2026-29972

Vulnerability from fkie_nvd - Published: 2026-05-08 16:16 - Updated: 2026-05-13 15:46
Severity
8.2 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Summary
nanoMODBUS through v1.22.0 has a stack-based buffer overflow in recv_read_registers_res() in nanomodbus.c. When a client calls nmbs_read_holding_registers() or nmbs_read_input_registers(), the library writes register data from the server response to the caller-provided buffer based on the response's byte_count field before validating that byte_count matches the requested quantity. A malicious Modbus TCP server can send a response with byte_count=250 (125 registers) regardless of the requested quantity, causing up to 248 bytes of attacker-controlled data to overflow the buffer, potentially allowing remote code execution.
References
cve@mitre.orghttps://gist.github.com/dwilliams27/a4e26fe747c8561d608f7549804bd85f
cve@mitre.orghttps://github.com/debevv/nanoMODBUS
cve@mitre.orghttps://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c#L580-L615
Impacted products
Vendor Product Version
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "nanoMODBUS through v1.22.0 has a stack-based buffer overflow in recv_read_registers_res() in nanomodbus.c. When a client calls nmbs_read_holding_registers() or nmbs_read_input_registers(), the library writes register data from the server response to the caller-provided buffer based on the response\u0027s byte_count field before validating that byte_count matches the requested quantity. A malicious Modbus TCP server can send a response with byte_count=250 (125 registers) regardless of the requested quantity, causing up to 248 bytes of attacker-controlled data to overflow the buffer, potentially allowing remote code execution."
    }
  ],
  "id": "CVE-2026-29972",
  "lastModified": "2026-05-13T15:46:19.993",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.2,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-08T16:16:09.960",
  "references": [
    {
      "source": "cve@mitre.org",
      "url": "https://gist.github.com/dwilliams27/a4e26fe747c8561d608f7549804bd85f"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/debevv/nanoMODBUS"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c#L580-L615"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-121"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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