{"id":"CVE-2026-71255","aliases":["EUVD-2026-53332","GHSA-9rfp-q4v5-653h"],"status":"published","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.","severity":{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00385,"percentile":0.32901,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-787"],"published":"2026-08-05T11:44:21Z","modified":"2026-10-28T02:31:14Z","products":[{"vendor":"debevv","product":"nanomodbus"}],"references":[{"url":"https://github.com/debevv/nanoMODBUS","tags":["third-party-advisory","advisory"]},{"url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71255","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-9rfp-q4v5-653h"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71255.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-71255","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.","status":"published","published":"2026-08-05T11:44:21.097Z","modified":"2026-08-10T11:46:16.03Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:19:49.559463Z"}],"euvd":[{"id":"EUVD-2026-53332","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.","status":"published","published":"2026-08-05T11:44:21Z","modified":"2026-08-10T11:46:16Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"updated_at":"2026-11-02T18:02:05.732685Z"}],"ghsa":[{"id":"GHSA-9rfp-q4v5-653h","title":"nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side...","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.","status":"published","published":"2026-08-05T12:31:33Z","modified":"2026-08-05T12:31:41Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T15:10:06.632203Z"}],"nvd":[{"id":"CVE-2026-71255","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.","status":"published","published":"2026-08-05T12:18:57.727Z","modified":"2026-10-24T15:10:00.19Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:12:35.031043Z"}],"osv":[{"id":"CVE-2026-71255","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.","status":"published","published":"2026-08-05T11:44:21.097Z","modified":"2026-10-28T02:31:14.664229488Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T15:45:15.164658Z"}]}}