CVE-2013-6920: Siemens SINAMICS S/G controllers with firmware before 4.6.11 do not require authentication for FTP and TELN...

Security readout for executives and security teams

This flaw means some Siemens SINAMICS S/G drive controllers could accept FTP or Telnet connections without authentication. If those services are reachable, an attacker may bypass intended access controls. The sources do not report active exploitation. Exposure is likely where Siemens SINAMICS S/G controllers run firmware before 4.6.11 and TCP ports 21 or 23 are reachable from untrusted networks. Treat this as a high-priority industrial control exposure if affected controllers are network-reachable. Prioritize discovery, segmentation, and vendor-approved firmware remediation. Mitigation focus: Identify Siemens SINAMICS S/G controllers and firmware versions.; Upgrade affected controllers to firmware 4.6.11 or later per Siemens guidance.; Restrict TCP ports 21 and 23 to trusted management networks..

Prepared

Jun 14, 2026, 15:13 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.