CVE-2021-40358

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

1.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-11-09 12:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:06 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.3% in the next 30 days (EPSS).
• Severity: 9.9 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-11-09 12:15 UTC

Last modified

2026-06-17 04:06 UTC

Exploit probability

1.3% · EPSS, next 30 days

Weakness

CWE-22 · Path traversal

Record status

Modified

Affected

• 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

Attack profile CVSS 3.1 · 9.9

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-40358.md and follow it. Check whether this project is affected by CVE-2021-40358. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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