CVE-2021-42029

Privilege escalation via mishandled user configuration

Published Apr 12, 2022 · Updated Aug 4, 2024

Improper access control in Siemens SIMATIC STEP 7 (TIA Portal) allows attackers to escalate privileges on configured device web servers. During a configuration download, the engineering software incorrectly handles web-server user-management settings, which can leave permissions broader than intended. Exploitation requires direct access to an activated S7-1200 or S7-1500 family web server whose configuration was downloaded by an affected release.

CVSS severity6.4
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

Improper access control in Siemens SIMATIC STEP 7 (TIA Portal) allows attackers to escalate privileges on configured device web servers. During a configuration download, the engineering software incorrectly handles web-server user-management settings, which can leave permissions broader than intended. Exploitation requires direct access to an activated S7-1200 or S7-1500 family web server whose configuration was downloaded by an affected release.

The record

CVE
CVE-2021-42029
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Siemens
Product
SIMATIC STEP 7 (TIA Portal)
Classifications
CWE-284, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 12, 2022CVE 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
  2. Affected versionversion=All versions < V16 Update 5
  3. Affected versionversion=All versions < V17 Update 2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Siemens · SIMATIC STEP 7 (TIA Portal)version=All versions; version=All versions < V16 Update 5; version=All versions < V17 Update 2

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.4Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:L/A:L
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1068Exploitation for Privilege Escalation

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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