CVE-2021-40358

Name: CVE-2021-40358
Creator: NVD / NIST
Published: 2021-11-09T12:15:09.93+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.9/10EPSS 1.23%

Last modified Jun 17, 2026

CVE-2021-40358 is a critical-severity vulnerability rated 9.9/10 on the CVSS scale. A vulnerability has been identified in SIMATIC PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMATIC WinCC V16 (All versions < V16 Update 5), SIMATIC WinCC V17 (All versions < V17 Update 2), SIMATIC WinCC V7.4 (All versions < V7.4 SP1 Update 19), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 5). Legitimate file operations on the web server of the affected systems do not properly neutralize special elements within the pathname. EPSS estimates a 1.23% chance of exploitation in the next 30 days.

Description

A vulnerability has been identified in SIMATIC PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMATIC WinCC V16 (All versions < V16 Update 5), SIMATIC WinCC V17 (All versions < V17 Update 2), SIMATIC WinCC V7.4 (All versions < V7.4 SP1 Update 19), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 5). Legitimate file operations on the web server of the affected systems do not properly neutralize special elements within the pathname. An attacker could then cause the pathname to resolve to a location outside of the restricted directory on the server and read, write or delete unexpected critical files.

Metrics

CVSS 3.1

9.9/10

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

EPSS Probability

1.23%

65.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Siemens	Simatic Pcs 7	8.2	—
Siemens	Simatic Pcs 7	9.0	—
Siemens	Simatic Pcs 7	9.1	—
Siemens	Simatic Wincc	7.4	—
Siemens	Simatic Wincc	7.5	—
Siemens	Simatic Wincc	15	—
Siemens	Simatic Wincc	15.1	—
Siemens	Simatic Wincc	16	Update1
Siemens	Simatic Wincc	17	—

References

https://cert-portal.siemens.com/productcert/pdf/ssa-840188.pdfVendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-840188.pdfVendor Advisory

Timeline

Published: Nov 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-40358?

How severe is CVE-2021-40358?

CVE-2021-40358 has a CVSS score of 9.9/10 (CRITICAL severity). The EPSS model estimates a 1.23% probability of exploitation in the next 30 days.

How do I fix CVE-2021-40358?

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-2021-40358?

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

Scan your code now

Source: NVD / NIST