{"id":"CVE-2026-71254","published":"2026-08-05T12:18:57.600","lastModified":"2026-08-10T12:17:27.960","description":"nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus server-side handle_read_file_record function (FC 0x14, Read File Record) in nanomodbus.c. The function validates that the total request size does not exceed 245 bytes and that each sub-request's record_length is at most 124, but it never validates the CUMULATIVE response size across all sub-requests before processing them.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-787"],"vendors":[],"products":[],"references":[{"url":"https://github.com/debevv/nanoMODBUS","tags":[]},{"url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c","tags":[]}],"exploitRefs":[{"url":"https://github.com/debevv/nanoMODBUS","tags":[]},{"url":"https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows an attacker to perform out-of-bounds writes by manipulating Modbus requests, leading to potential code execution or data corruption.","exploitability":"Exploitation is moderately difficult requiring knowledge of Modbus protocol and specific request crafting; preconditions include access to the affected nanoMODBUS server.","blast_radius":"If exploited, this could lead to significant damage including system compromise or operational disruption in industrial control systems.","remediation":"Update to the latest version of nanoMODBUS that addresses this vulnerability or apply a patch if available.","tags":["modbus","ics","write-attack","patch-recommended"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-08-11T06:43:25.446Z"}}