{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-54410", "assignerOrgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "state": "PUBLISHED", "assignerShortName": "TuranSec", "dateReserved": "2026-06-13T16:39:46.122Z", "datePublished": "2026-06-14T17:10:12.275Z", "dateUpdated": "2026-08-10T11:43:54.292Z" }, "containers": { "cna": { "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-193", "description": "CWE-193 Off-by-one Error", "type": "CWE" } ] }, { "descriptions": [ { "lang": "en", "cweId": "CWE-787", "description": "CWE-787 Out-of-bounds Write", "type": "CWE" } ] } ], "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." } ] } ], "affected": [ { "vendor": "debevv", "product": "nanoMODBUS", "collectionURL": "https://github.com/debevv/nanoMODBUS", "repo": "https://github.com/debevv/nanoMODBUS", "programFiles": [ "nanomodbus.c" ], "programRoutines": [ { "name": "recv_msg_header" } ], "versions": [ { "status": "affected", "version": "0", "lessThanOrEqual": "1.23.0", "versionType": "semver" } ], "defaultStatus": "unknown" } ], "descriptions": [ { "lang": "en", "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.", "supportingMedia": [ { "type": "text/html", "base64": false, "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.

" } ] } ], "references": [ { "url": "https://github.com/debevv/nanoMODBUS", "name": "nanoMODBUS - upstream repository (vendor)", "tags": [ "product" ] }, { "url": "https://github.com/debevv/nanoMODBUS/blob/v1.23.0/nanomodbus.c#L369", "name": "Vulnerable bounds check at nanomodbus.c line 369 (v1.23.0)", "tags": [ "product" ] }, { "url": "https://cwe.mitre.org/data/definitions/193.html", "name": "CWE-193: Off-by-one Error", "tags": [ "technical-description" ] }, { "url": "https://cwe.mitre.org/data/definitions/787.html", "name": "CWE-787: Out-of-bounds Write", "tags": [ "technical-description" ] } ], "metrics": [ { "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." } ], "cvssV4_0": { "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "Safety": "NOT_DEFINED", "Automatable": "YES", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 7.8, "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" } }, { "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ], "cvssV3_1": { "version": "3.1", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "HIGH", "baseSeverity": "HIGH", "baseScore": 8.6, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H" } }, { "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ], "cvssV2_0": { "version": "2.0", "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "NONE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "COMPLETE", "baseScore": 9, "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:C" } } ], "credits": [ { "lang": "en", "value": "Burxonov Muslimbek", "type": "finder" } ], "source": { "discovery": "EXTERNAL" }, "x_author": "Burxonov Muslimbek", "x_assigner_notes": "Vendor 'debevv' 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 'unknown' pending vendor confirmation of a fixed release. CVSS scoring follows the submitter's 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).", "title": "nanoMODBUS Off-by-One Buffer Overflow in recv_msg_header() via Crafted MBAP Length Field", "providerMetadata": { "orgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "shortName": "TuranSec", "dateUpdated": "2026-08-10T11:43:54.292Z" }, "datePublic": "2026-06-14T17:10:12.275Z" }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-15T17:00:11.456275Z", "id": "CVE-2026-54410", "options": [ { "Exploitation": "none" }, { "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": "2026-06-15T17:05:25.499Z" } } ] } }