CVE-2021-40364

Local information disclosure via sensitive-data logging

Published Nov 9, 2021 · Updated Aug 4, 2024

Sensitive-data logging in Siemens SIMATIC WinCC and PCS 7 allows local users to read information recorded in application log files. The advisory does not identify the affected log files, the sensitive fields, or the logging routine that writes them. Exploitation requires low-privilege local access to those files and exposes recorded information for disclosure or use in follow-on attacks.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sensitive-data logging in Siemens SIMATIC WinCC and PCS 7 allows local users to read information recorded in application log files. The advisory does not identify the affected log files, the sensitive fields, or the logging routine that writes them. Exploitation requires low-privilege local access to those files and exposes recorded information for disclosure or use in follow-on attacks.

The record

CVE
CVE-2021-40364
Published
Nov 9, 2021
Updated
Aug 4, 2024
Vendor
Siemens
Product
SIMATIC WinCC
Classifications
CWE-532, T1005
Attack vector
local
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 vectorlocal
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

2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N
5.5Siemens AGCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-532Insertion of Sensitive Information into Log File
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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