---
title: "CVE-2026-4129: NI SystemLink - Broken Access Control"
description: "NI SystemLink and NI SystemLink Server <= 2026 Q3 contain an improper access control vulnerability caused by insufficient restrictions on host OS files and directories, letting authenticated users with limited privileges access restricted files."
url: https://panop.io/threat-heartbeat/CVE-2026-4129/
---

# CVE-2026-4129 NI SystemLink - Broken Access Control

NI SystemLink and NI SystemLink Server <= 2026 Q3 contain an improper access control vulnerability caused by insufficient restrictions on host OS files and directories, letting authenticated users with limited privileges access restricted files.

CVSS base score 8.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.35% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-4129)

## Details

Type

Broken Access Control

Impact

Information Disclosure, File System Read

CVSS vector

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

Published

10 September 2026

Updated

15 October 2026

Weakness

[CWE-862](https://cwe.mitre.org/data/definitions/862.html)

## Vendor fix

Update to the latest version beyond 2026 Q3.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-4129](https://nvd.nist.gov/vuln/detail/CVE-2026-4129)
- [https://www.ni.com/en/support/security/available-critical-and-security-updates-for-ni-software/2026/improper-access-controls-in-ni-systemlink.html](https://www.ni.com/en/support/security/available-critical-and-security-updates-for-ni-software/2026/improper-access-controls-in-ni-systemlink.html)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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