CVE-2021-40358Network attack vector

Arbitrary file access via web server path traversal

Published Nov 9, 2021 · Updated Aug 4, 2024

Path traversal in the web server of Siemens SIMATIC WinCC and SIMATIC PCS 7 allows remote authenticated users to read, write, or delete files. The server performs file operations without neutralizing special pathname elements, allowing paths to escape the restricted directory. Low-privilege credentials and an enabled web server are required; successful requests expose, alter, or delete critical files.

CVSS severity9.9
Critical
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in the web server of Siemens SIMATIC WinCC and SIMATIC PCS 7 allows remote authenticated users to read, write, or delete files. The server performs file operations without neutralizing special pathname elements, allowing paths to escape the restricted directory. Low-privilege credentials and an enabled web server are required; successful requests expose, alter, or delete critical files.

The record

CVE
CVE-2021-40358
Published
Nov 9, 2021
Updated
Aug 4, 2024
Vendor
Siemens
Product
SIMATIC WinCC
Classifications
CWE-22, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=All versions < V15 SP1 Update 7
  2. Affected versionversion=All versions < V16 Update 5
  3. Affected versionversion=All versions < V17 Update 2
  4. Affected versionversion=All versions < V7.4 SP1 Update 19
  5. Affected versionversion=All versions < V7.5 SP2 Update 5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC WinCCversion=All versions < V15 SP1 Update 7; version=All versions < V16 Update 5; version=All versions < V17 Update 2; version=All versions < V7.4 SP1 Update 19; version=All versions < V7.5 SP2 Update 5
Siemens · SIMATIC PCS 7version=All versions; version=All versions < V9.0 SP3 UC04; version=All versions < V9.1 SP1

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.9Siemens ProductCERTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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