CVE-2021-31337: Siemens Sinamics SL150 Firmware

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

The Telnet service of the SIMATIC HMI Comfort Panels system component in affected products does not require authentication, which may allow a remote attacker to gain access to the device if the service is enabled. Telnet is disabled by default on the SINAMICS Medium Voltage Products (SINAMICS SL150: All versions, SINAMICS SM150: All versions, SINAMICS SM150i: All versions).

Affected products

• Siemens Sinamics SL150 Firmware: any version
• Siemens Sinamics SM150 Firmware: any version
• Siemens Sinamics SM150I Firmware: any version

Published 2021-06-28. Last modified 2026-06-17.