SecuriTricks - CVE-2026-29972

Description

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.

Product(s) Impacted

Vendor	Product	Versions
Nanomodus	Nanomodbus	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-121

Stack-based Buffer Overflow

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	nanomodus	nanomodbus	/	/	/	/	/	/	/	/

References

https://gist.github.com/dwilliams27/a4e26fe747c8561d608f7549804bd85f

https://github.com/debevv/nanoMODBUS

https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c#L580-L615

CVSS Score

8.2 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: LOW
Availability Impact: HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

View Vector String

Timeline

Published: May 8, 2026, 4:16 p.m.
Last Modified: May 8, 2026, 5:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-29972