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.

Overview

State: PUBLISHED
Assigner (CNA): mitre
CVSS severity: high
CVSS score: 8.2 / 10
CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Effective score: 8.2 / 10 HIGH source: CNA overview
CWE(s): —
Reserved: 2026-03-04
Published: 2026-05-08 02:00 UTC
Last updated: 2026-05-08 17:59 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/29xxx/CVE-2026-29972.json
Linked Threat: CVE-2026-29972 — CVE-2026-29972

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-08 16:16:09 UTC
NVD last modified: 2026-05-13 15:46:19 UTC
NVD CVSS v3.1: 8.2 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Exploitability subscore: 3.9 / 10
Impact subscore: 4.2 / 10
EPSS score: 0.0007 (probability of exploitation in next 30 days)
EPSS percentile: 20.80% vs all CVEs — higher = more likely to be exploited, as of 2026-05-25

NVD-assigned CWE(s): CWE-121 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-28785
Assigner: mitre
Published: May 8, 2026, 12:00:00 AM
Updated: May 8, 2026, 3:59:03 PM
EUVD base score (CVSS 3.1): 8.2 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
EUVD-reported EPSS: 0.0700
Vendors: n/a
Products: n/a (n/a)

ENISA 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.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
n/a	n/a	`n/a` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

MITRE references (3) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (3)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

https://nvd.nist.gov/vuln/detail/CVE-2026-29972 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-29972 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://gist.github.com/dwilliams27/a4e26fe747c8561d608f7549804bd85f cve@mitre.org
https://github.com/debevv/nanoMODBUS cve@mitre.org
https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c#L580-L615 cve@mitre.org

Remediations (16)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Mitigate RedSun Zero-Day Without A Patch | Qualys

web:blog.qualys.com

RedSun is a zero-day LPE in Microsoft Defender with no patch available. Learn how to detect and mitigate it instantly using Qualys VMDR and TruRisk™ Eliminate.

2026-05-23 21:07 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-05-23 21:07 UTC
Addressing Exchange Server May 2026 vulnerability CVE-2026-42897

web:techcommunity.microsoft.com

Known issues when mitigation is applied We are aware of following known issues once CVE - 2026 -42897 mitigation is applied (using either option above): OWA Print Calendar functionality might not work. As a workaround copy the data or screenshot the calendar you want to print or use Outlook Desktop client.

2026-05-23 21:07 UTC
CVE-2026-42897 Exchange OWA Mitigation M2: What Admins Must Verify

web:windowsforum.com

Microsoft's Fastest Fix Is a Mitigation , Not a Patch The important detail in Microsoft's May 14 notice is that there is no permanent Exchange security update available yet for CVE - 2026 -42897. Microsoft says it is working on one and will release it later for affected supported paths, but today's defensive action is mitigation .

2026-05-23 21:07 UTC
Microsoft April 2026 Patch Tuesday fixes 167 flaws, 2 zero-days

web:www.bleepingcomputer.com

Today is Microsoft's April 2026 Patch Tuesday with security updates for 167 flaws, including 2 zero-day vulnerabilities.

2026-05-23 21:07 UTC
April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

2026-05-23 21:07 UTC
CVE: Common Vulnerabilities and Exposures

web:www.cve.org

At cve .org, we provide the authoritative reference method for publicly known information-security vulnerabilities and exposures

2026-05-23 21:07 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

Oracle Critical Patch Update Advisory - April 2026 Description A Critical Patch Update is a collection of patches for multiple security vulnerabilities. These patches address vulnerabilities in Oracle code and in third party components included in Oracle products. These patches are usually cumulative, but each advisory describes only the security patches added since the previous Critical Patch ...

2026-05-23 21:07 UTC
Quantifying 2026 Routinely Targeted Vulnerabilities (So Far)

web:www.vulncheck.com

VulnCheck identified 25 CVEs disclosed in 2026 that have been routinely targeted by adversaries and researchers so far this year, drawing from a global body of exploit code and exploitation data.

2026-05-23 21:07 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-23 21:07 UTC
Don't wait to update: iOS 26.2 addresses multiple vulnerabilities

web:appleinsider.com

A kernel-related fix in iOS 26.2 prevents apps from gaining root privileges. Apple also included four separate fixes to prevent memory corruption on iOS 26.2.

2026-05-26 02:47 UTC
Patch Tuesday - Cisco Talos Blog

web:blog.talosintelligence.com

Microsoft Patch Tuesday for October 2025 — Snort rules and prominent vulnerabilities Microsoft has released its monthly security update for October 2025, addressing 175 Microsoft CVEs and 21 non-Microsoft CVEs . Among these, 17 vulnerabilities are considered critical and 11 are flagged as important and considered more likely to be exploited.

2026-05-26 02:47 UTC
About the security content of iOS 26.2 and iPadOS 26.2

web:support.apple.com

This document describes the security content of iOS 26.2 and iPadOS 26.2.

2026-05-26 02:47 UTC
Microsoft's May 2026 Patch Tuesday Fixes 130+ Vulnerabilities ...

web:windowsreport.com

Microsoft has released its May 2026 Patch Tuesday updates for Windows 11 and Windows 10, shipping as KB5089549 and KB5087544. The updates include fixes for more than 130 security vulnerabilities across Windows, Office, SharePoint, DNS components, and core system services, as Bleeping Computer writes. While no publicly disclosed zero-day vulnerabilities were reported this month, the […]

2026-05-26 02:47 UTC
Microsoft warns of Exchange zero-day flaw exploited in attacks

web:www.bleepingcomputer.com

On Thursday, Microsoft shared mitigations for a high-severity Exchange Server vulnerability exploited in attacks that allow threat actors to execute arbitrary code via cross-site scripting (XSS ...

2026-05-26 02:47 UTC
Microsoft Confirms Active 0-Day Exploit—Check Emergency Mitigation

web:www.forbes.com

Updated May 18: This article has been updated to include further details on the emergency mitigation process recommended by Microsoft after the CVE - 2026 -42897 Exchange Server zero-day was ...

2026-05-26 02:47 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-29972.json.

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