CVE-2021-31892Network attack vector

TLS traffic interception via overwritten SSL flags

Published Jul 13, 2021 · Updated Aug 3, 2024

Improper certificate validation in Siemens SINUMERIK applications allows man-in-the-middle attackers to read or alter TLS traffic. A third-party dependency overwrites the SSL flags used when creating a server connection, disabling validation of the server certificate. Exploitation requires a network position from which attackers can intercept the affected application's outbound TLS connection and impersonate its server.

CVSS severity7.4
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Siemens SINUMERIK applications allows man-in-the-middle attackers to read or alter TLS traffic. A third-party dependency overwrites the SSL flags used when creating a server connection, disabling validation of the server certificate. Exploitation requires a network position from which attackers can intercept the affected application's outbound TLS connection and impersonate its server.

The record

CVE
CVE-2021-31892
Published
Jul 13, 2021
Updated
Aug 3, 2024
Vendor
Siemens
Product
SINUMERIK Manage MyResources /Programs
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

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

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SINUMERIK Manage MyResources /Programsversion=All versions
Siemens · SINUMERIK Integrate for Productionversion=All versions < V4.1 SP10 HF3; version=V5.1
Siemens · SINUMERIK Manage MyMachines /Remoteversion=All versions
Siemens · SINUMERIK Operateversion=All versions < V4.8 SP8; version=All versions < V4.93 HF7; version=All versions < V4.94 HF5
Siemens · SINUMERIK Manage MyMachinesversion=All versions
Siemens · SINUMERIK Manage MyProgramsversion=All versions
Siemens · SINUMERIK Analyze MyPerformanceversion=All versions
Siemens · SINUMERIK Analyze MyPerformance /OEE Tuningversion=All versions
Siemens · SINUMERIK Manage MyResources /Toolsversion=All versions
Siemens · SINUMERIK Manage MyMachines /Spindle Monitorversion=All versions
Siemens · SINUMERIK Manage MyToolsversion=All versions
Siemens · SINUMERIK Analyze MyConditionversion=All versions
Siemens · SINUMERIK Optimize MyProgramming /NX-Cam Editorversion=All versions
Siemens · SINUMERIK Analyze MyPerformance /OEE Monitorversion=All versions
Siemens · SINUMERIK Integrate Clientversion=All versions >= V02.00.12 < 02.00.18; version=All versions >= V03.00.12 < 03.00.18; version=V04.00.02 and all versions >= V04.00.15 < 04.00.18

Published CVSS scores

5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:N
7.4NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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.

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No observations available

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

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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