CVE-2021-31894

Device manipulation via writable configuration metafiles

Published Jul 13, 2021 · Updated Aug 3, 2024

Incorrect directory permissions in Siemens SIMATIC engineering software allow local users to alter device-configuration metafiles. A directory used for device configuration metadata grants write access to low-privileged users, who can replace or modify files consumed during later configuration. Local access to an engineering station is required, and successful tampering can change device parameters or behavior, including operational disruption.

CVSS severity8.8
High
EPSS probability0.23%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect directory permissions in Siemens SIMATIC engineering software allow local users to alter device-configuration metafiles. A directory used for device configuration metadata grants write access to low-privileged users, who can replace or modify files consumed during later configuration. Local access to an engineering station is required, and successful tampering can change device parameters or behavior, including operational disruption.

The record

CVE
CVE-2021-31894
Published
Jul 13, 2021
Updated
Aug 3, 2024
Vendor
Siemens
Product
SIMATIC STEP 7
Classifications
CWE-732, T1565.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 < V5.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC STEP 7version=All versions < V5.7
Siemens · SIMATIC PDMversion=All versions < V9.2 SP2
Siemens · SINAMICS STARTERversion=All versions < V5.4 SP2 HF1
Siemens · SIMATIC PCS 7version=All versions; version=All versions < V9.1 SP2

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
T1565.001Stored Data Manipulation

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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