CVE-2026-4129: Improper Access Controls in NI SystemLink

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-10 · updated 2026-09-16
Weakness: CWE-862

Description

There is an improper access control vulnerability in NI SystemLink that may allow an authenticated user with limited privileges to access host operating system files and directories that should be restricted. This vulnerability affects NI SystemLink and NI SystemLink Server versions prior to 2026 Q3.

Affected products

NI SystemLink: before 26.5.0 — fixed in 26.5.0
NI SystemLink Server: before 26.5.0 — fixed in 26.5.0

How to fix

Upgrade to a fixed version: NI SystemLink 26.5.0; NI SystemLink Server 26.5.0. Check the vendor advisory for mitigations.

References

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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