{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/debevv/nanoMODBUS",
          "defaultStatus": "unknown",
          "product": "nanoMODBUS",
          "programFiles": [
            "nanomodbus.c"
          ],
          "programRoutines": [
            {
              "name": "recv_msg_header"
            }
          ],
          "repo": "https://github.com/debevv/nanoMODBUS",
          "vendor": "debevv",
          "versions": [
            {
              "lessThanOrEqual": "1.23.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Burxonov Muslimbek"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003enanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the recv_msg_header() function of the Modbus/TCP server that allows remote unauthenticated attackers to write one attacker-controlled byte past the end of the 260-byte receive buffer by sending a crafted MBAP frame whose Length field is set to 255. The overflow corrupts the adjacent buffer-index field of the nanoMODBUS state structure, resulting in denial of service through invalid memory accesses and, on bare-metal and RTOS targets without memory protection, one-byte information disclosure and writes to unintended register addresses on the Write Multiple Registers (FC16) handler path.\u003c/p\u003e"
            }
          ],
          "value": "nanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the recv_msg_header() function of the Modbus/TCP server that allows remote unauthenticated attackers to write one attacker-controlled byte past the end of the 260-byte receive buffer by sending a crafted MBAP frame whose Length field is set to 255. The overflow corrupts the adjacent buffer-index field of the nanoMODBUS state structure, resulting in denial of service through invalid memory accesses and, on bare-metal and RTOS targets without memory protection, one-byte information disclosure and writes to unintended register addresses on the Write Multiple Registers (FC16) handler path."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "A remote unauthenticated attacker who can reach a Modbus/TCP server built on nanoMODBUS can send a crafted MBAP frame with the Length field set to 255 to overflow the 260-byte receive buffer by one byte, corrupting the adjacent buf_idx field of the nmbs_t struct with an attacker-controlled value. This yields denial of service (subsequent handler calls treat the corrupted buf_idx as a register count / offset and crash, hang, or return invalid data), one-byte information disclosure on bare-metal and RTOS targets without memory protection (ARM Cortex-M, ESP32, STM32 class), and the possibility of writing to unintended register addresses on the FC16 (Write Multiple Registers) handler path. No authentication, no user interaction, and no special configuration are required."
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "YES",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "exploitMaturity": "PROOF_OF_CONCEPT",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/AU:Y",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "An attacker who can reach the TCP listening port of a Modbus/TCP server built on nanoMODBUS (typically TCP/502 on industrial / OT networks) sends a single crafted MBAP frame with Length=255 to corrupt the buf_idx field of the nmbs_t struct, causing denial of service or, on memory-protection-less embedded targets, additional information disclosure or unintended register writes."
            }
          ]
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV2_0": {
            "accessComplexity": "LOW",
            "accessVector": "NETWORK",
            "authentication": "NONE",
            "availabilityImpact": "COMPLETE",
            "baseScore": 9,
            "confidentialityImpact": "PARTIAL",
            "integrityImpact": "PARTIAL",
            "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:C",
            "version": "2.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-193",
              "description": "CWE-193 Off-by-one Error",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787 Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:10:12.275Z",
        "orgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "shortName": "TuranSec"
      },
      "references": [
        {
          "name": "nanoMODBUS - upstream repository (vendor)",
          "tags": [
            "product"
          ],
          "url": "https://github.com/debevv/nanoMODBUS"
        },
        {
          "name": "Vulnerable bounds check at nanomodbus.c line 369 (v1.23.0)",
          "tags": [
            "product"
          ],
          "url": "https://github.com/debevv/nanoMODBUS/blob/v1.23.0/nanomodbus.c#L369"
        },
        {
          "name": "CWE-193: Off-by-one Error",
          "tags": [
            "technical-description"
          ],
          "url": "https://cwe.mitre.org/data/definitions/193.html"
        },
        {
          "name": "CWE-787: Out-of-bounds Write",
          "tags": [
            "technical-description"
          ],
          "url": "https://cwe.mitre.org/data/definitions/787.html"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "x_assigner_notes": "Vendor \u0027debevv\u0027 is a single-maintainer GitHub account; nanoMODBUS is MIT-licensed. The vulnerable bounds check was verified by source inspection of v1.22.0, v1.22.1, and v1.23.0 (latest at publish time) - the issue is present in all three; affected range is therefore 0 through v1.23.0 (inclusive) with defaultStatus \u0027unknown\u0027 pending vendor confirmation of a fixed release. CVSS scoring follows the submitter\u0027s CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H = 8.6) and translates to 4.0 with VC:L/VI:L/VA:H, SC/SI/SA:N (= 8.7) and 2.0 with C:P/I:P/A:C (= 9.0).",
      "x_author": "Burxonov Muslimbek",
      "x_generator": {
        "engine": "Vulnogram 1.0.2"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
    "assignerShortName": "TuranSec",
    "cveId": "CVE-2026-54410",
    "datePublished": "2026-06-14T17:10:12.275Z",
    "dateReserved": "2026-06-13T16:39:46.122Z",
    "dateUpdated": "2026-06-14T17:10:12.275Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}