CVE-2021-40368

Severity: medium (CVSS 5.0 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-04-12 · updated 2026-06-17
Weakness: CWE-119

Description

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: all versions
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: all versions

How to fix

Upgrade to a fixed version: Siemens Simatic S7-400H V6 Firmware 6.0.10; Siemens Simatic S7-410 V10 Firmware 10.1. Check the vendor advisory for mitigations.

References

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