CVE-2021-40368: Siemens SIMATIC s7-400 Pn/dp v7 Firmware

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

A vulnerability has been identified in SIMATIC S7-400 CPU 412-1 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 414-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 414F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416-2 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416F-2 DP V7 (All versions), SIMATIC S7-400 CPU 416F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 417-4 DP V7 (All versions), SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants) (All versions < V6.0.10), SIMATIC S7-410 V10 CPU family (incl. SIPLUS variants) (All versions < V10.1), SIMATIC S7-410 V8 CPU family (incl. SIPLUS variants) (All versions < V8.2.3), SIPLUS S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 V7 (All versions), SIPLUS S7-400 CPU 417-4 V7 (All versions). Affected devices improperly handle specially crafted packets sent to port 102/tcp. This could allow an attacker to create a Denial-of-Service condition. A restart is needed to restore normal operations.

Affected products

• Siemens SIMATIC s7-400 Pn/dp v7 Firmware: any version
• Siemens SIMATIC s7-400h v6 Firmware: before 6.0.10 (fixed in 6.0.10)
• Siemens SIMATIC s7-410 v10 Firmware: before 10.1 (fixed in 10.1)
• Siemens SIMATIC s7-410 v8 Firmware: any version

Published 2022-04-12. Last modified 2026-06-17.