{"id":"CVE-2026-29972","details":"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.","modified":"2026-07-15T01:49:01.527015497Z","published":"2026-05-08T00:00:00Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29972.json","cna_assigner":"mitre"},"references":[{"type":"WEB","url":"https://gist.github.com/dwilliams27/a4e26fe747c8561d608f7549804bd85f"},{"type":"WEB","url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c#L580-L615"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29972.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29972"},{"type":"PACKAGE","url":"https://github.com/debevv/nanoMODBUS"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/debevv/nanomodbus","events":[{"introduced":"0"},{"fixed":"035b8d596a954c2dd4bc40e3fa28a7cb2a8c0ec1"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"v1.22.0"}],"source":"DESCRIPTION"}}],"versions":["v1.21.0","v1.20.1","v1.20.0","v1.19.0","v1.18.1","v1.17.3","v1.17.2","v1.17.1","v1.17.0","v1.16.0","v1.15.0","v1.14.3","v1.14.2","v1.14.1","v1.14.0","v1.13.0","v1.12.1","v1.12.0","v1.11.0","v1.10.0","v1.9.1","v1.9.0","v1.8.1","v1.8.0","v1.7.0","v1.6.0","v1.5.0","v1.4.0","v1.3.1","v1.3.0","v1.2.1","v1.2.0","v1.1.1","v1.1.0","v1.0.1","v1.0.0","v1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-29972.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"}]}