CVE-2016-3949: Siemens SIMATIC s7-300 With Profitnet Support Firmware

High severity, CVSS 7.5. EPSS: 4.5% chance of exploitation in the next 30 days.

Siemens SIMATIC S7-300 Profinet-enabled CPU devices with firmware before 3.2.12 and SIMATIC S7-300 Profinet-disabled CPU devices with firmware before 3.3.12 allow remote attackers to cause a denial of service (defect-mode transition) via crafted (1) ISO-TSAP or (2) Profibus packets.

Affected products

• Siemens SIMATIC s7-300 With Profitnet Support Firmware: version 3.2.11 only
• Siemens SIMATIC s7-300 Without Profitnet Support Firmware: version 3.3.11 only

Published 2016-06-27. Last modified 2026-06-17.