CVE-2026-29972

High

Published: 08 May 2026

Published

08 May 2026

Modified

13 May 2026

KEV Added

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Patch

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CVSS Score v3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS Score 0.0064 46.1th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-29972 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability. Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 46.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-28785

Vulnerability 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.

CWE(s): CWE-121

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

Why these techniques?

Stack buffer overflow in Modbus client response parsing enables attacker-controlled RCE via malicious server, directly mapping to client-side exploitation technique.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0