CVE-2021-40368

Name: CVE-2021-40368
Creator: NVD / NIST
Published: 2022-04-12T09:15:13.343+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.94%

Last modified Jun 17, 2026

CVE-2021-40368 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.94% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.94%

56.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Siemens	Simatic S7-400h V6 Firmware	< 6.0.10
Siemens	Simatic S7-400 Pn\/Dp V7 Firmware	All versions
Siemens	Simatic S7-410 V8 Firmware	All versions
Siemens	Simatic S7-410 V10 Firmware	< 10.1

References

https://cert-portal.siemens.com/productcert/pdf/ssa-557541.pdfPatch, Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-557541.pdfPatch, Vendor Advisory

Timeline

Published: Apr 12, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-40368?

How severe is CVE-2021-40368?

CVE-2021-40368 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.94% probability of exploitation in the next 30 days.

How do I fix CVE-2021-40368?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-40368?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST