CVE-2026-29972

high

Published 2026-05-08 · Modified 2026-05-13

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CVSS v3

8.2

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

8.2

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.

Predictions

Exploit likelihood

88%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

CWEs

CWE-121

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.