CVE-2021-37172: Siemens SIMATIC s7-1200 CPU Firmware

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A vulnerability has been identified in SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (V4.5.0). Affected devices fail to authenticate against configured passwords when provisioned using TIA Portal V13. This could allow an attacker using TIA Portal V13 or later versions to bypass authentication and download arbitrary programs to the PLC. The vulnerability does not occur when TIA Portal V13 SP1 or any later version was used to provision the device.

Affected products

• Siemens SIMATIC s7-1200 CPU Firmware: version 4.5.0 only
• Siemens SIMATIC Step 7 (tia Portal): up to and including 13.0

Published 2021-08-10. Last modified 2026-06-17.