CVE-2021-27434: Unified-Automation .net Based Opc Ua Client/server SDK

High severity, CVSS 7.5. EPSS: 1.7% chance of exploitation in the next 30 days.

Products with Unified Automation .NET based OPC UA Client/Server SDK Bundle: Versions V3.0.7 and prior (.NET 4.5, 4.0, and 3.5 Framework versions only) are vulnerable to an uncontrolled recursion, which may allow an attacker to trigger a stack overflow.

Affected products

• Unified-Automation .net Based Opc Ua Client/server SDK: up to and including 3.0.7

Published 2021-05-20. Last modified 2026-06-17.