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Search Results (4 CVEs found)
| CVE | Vendors | Products | Updated | CVSS v3.1 |
|---|---|---|---|---|
| CVE-2026-71255 | 1 Debevv | 1 Nanomodbus | 2026-08-05 | 8.6 High |
| 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. | ||||
| CVE-2026-71254 | 1 Debevv | 1 Nanomodbus | 2026-08-05 | 9.8 Critical |
| 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. The accumulator response_data_size is declared as uint8_t and is incremented by 2 + record_length*2 for each of up to 35 sub-requests; with 35 sub-requests of record_length=124, the cumulative demand is 8750 bytes, which overflows the uint8_t accumulator. A subsequent loop then calls get_n(), an internal function with no bounds checking, once per sub-request to obtain a pointer into the 260-byte msg.buf receive buffer and advances the internal buf_idx by up to 248 bytes per call; swap_regs() then writes to that pointer unconditionally. A single crafted FC 0x14 request from an unauthenticated network client can cause up to ~8490 bytes to be written out of bounds past the 260-byte buffer, corrupting adjacent memory in the server process and leading to denial of service or potential remote code execution, particularly on embedded/bare-metal targets without memory protection. | ||||
| CVE-2026-71256 | 1 Debevv | 1 Nanomodbus | 2026-08-05 | 9.8 Critical |
| nanoMODBUS through v1.23.0 contains an out-of-bounds stack read leading to a wild-pointer write in nmbs_read_device_identification_basic() / recv_read_device_identification_res() in nanomodbus.c. A fixed 3-element stack array order[3] = {0,1,2} maps object IDs to buffer indices. The server-supplied object_id field (0-255, read directly from the wire) is used without any bounds check as buf_index = order[object_id]. When a malicious Modbus server sends a Read Device Identification response with object_id >= 3, this reads an out-of-bounds/garbage byte from the stack adjacent to order[], which is then used as an index into a 3-element buffers[] array of char* pointers. The resulting wild pointer is passed to strncpy() as the destination, causing an arbitrary-address write with server-controlled data. | ||||
| CVE-2026-54410 | 1 Debevv | 1 Nanomodbus | 2026-08-05 | 8.6 High |
| 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. The overflow corrupts the adjacent buffer-index field of the nanoMODBUS state structure, resulting in denial of service through invalid memory accesses and, on bare-metal and RTOS targets without memory protection, one-byte information disclosure and writes to unintended register addresses on the Write Multiple Registers (FC16) handler path. | ||||
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