{"api_version":"1","generated_at":"2026-08-06T18:53:05+00:00","cve":"CVE-2026-71255","urls":{"html":"https://cve.report/CVE-2026-71255","api":"https://cve.report/api/cve/CVE-2026-71255.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-71255","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-71255"},"summary":{"title":"nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()","description":"nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identification_res() function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied object_length field (0-246) is validated only against the remaining PDU size (res_size_left) and is never validated against the caller-supplied buffers_length parameter. After copying data with strncpy(buffers_out[buf_index], str, buffers_length), the code unconditionally writes a NUL terminator at buffers_out[buf_index][object_length]. When a malicious or compromised Modbus server sends a response with object_length greater than or equal to the client's buffers_length, this NUL write lands past the end of the caller-provided buffer, corrupting adjacent stack or heap memory on the client.","state":"PUBLISHED","assigner":"TuranSec","published_at":"2026-08-05 12:18:57","updated_at":"2026-08-05 13:24:49"},"problem_types":["CWE-787","CWE-787 CWE-787"],"metrics":[{"version":"3.1","source":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","type":"Secondary","score":"8.6","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","baseScore":8.6,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.6","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","data":{"baseScore":8.6,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"}}],"references":[{"url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c","name":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c","refsource":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/debevv/nanoMODBUS","name":"https://github.com/debevv/nanoMODBUS","refsource":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-71255","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71255","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"debevv","product":"nanoMODBUS","version":"affected 1.23.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Shukhratbek Uraiimov","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-71255","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-08-05T12:28:05.858513Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-08-05T12:29:13.596Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"nanoMODBUS","programFiles":["nanomodbus.c"],"vendor":"debevv","versions":[{"lessThanOrEqual":"1.23.0","status":"affected","version":"0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Shukhratbek Uraiimov"}],"descriptions":[{"lang":"en","value":"nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identification_res() function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied object_length field (0-246) is validated only against the remaining PDU size (res_size_left) and is never validated against the caller-supplied buffers_length parameter. After copying data with strncpy(buffers_out[buf_index], str, buffers_length), the code unconditionally writes a NUL terminator at buffers_out[buf_index][object_length]. When a malicious or compromised Modbus server sends a response with object_length greater than or equal to the client's buffers_length, this NUL write lands past the end of the caller-provided buffer, corrupting adjacent stack or heap memory on the client."}],"metrics":[{"cvssV3_1":{"baseScore":8.6,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-787","description":"CWE-787","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-08-05T12:52:21.582Z","orgId":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","shortName":"TuranSec"},"references":[{"url":"https://github.com/debevv/nanoMODBUS"},{"url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c"}],"title":"nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()"}},"cveMetadata":{"assignerOrgId":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","assignerShortName":"TuranSec","cveId":"CVE-2026-71255","datePublished":"2026-08-05T11:44:21.097Z","dateReserved":"2026-08-05T11:43:52.778Z","dateUpdated":"2026-08-05T12:52:21.582Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-05 12:18:57","lastModifiedDate":"2026-08-05 13:24:49","problem_types":["CWE-787","CWE-787 CWE-787"],"metrics":{"cvssMetricV31":[{"source":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","baseScore":8.6,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":4.7}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-05T12:28:05.858513Z","id":"CVE-2026-71255","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"71255","Ordinal":"1","Title":"nanoMODBUS Client-Side Out-of-Bounds Write via object_length in ","CVE":"CVE-2026-71255","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"71255","Ordinal":"1","NoteData":"nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identification_res() function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied object_length field (0-246) is validated only against the remaining PDU size (res_size_left) and is never validated against the caller-supplied buffers_length parameter. After copying data with strncpy(buffers_out[buf_index], str, buffers_length), the code unconditionally writes a NUL terminator at buffers_out[buf_index][object_length]. When a malicious or compromised Modbus server sends a response with object_length greater than or equal to the client's buffers_length, this NUL write lands past the end of the caller-provided buffer, corrupting adjacent stack or heap memory on the client.","Type":"Description","Title":"nanoMODBUS Client-Side Out-of-Bounds Write via object_length in "}]}}}