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Tf6100 FirmwareOperating system · Beckhoff

CVE-2021-34594

MEDIUM · 6.5 CVSS v3.1 Published 2021-11-04
Fix available
A fix is available. Upgrade to 4.3.48.0 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
TwinCAT OPC UA Server in TF6100 and TS6100 in product versions before 4.3.48.0 or with TcOpcUaServer versions below 3.2.0.194 are prone to a relative path traversal that allow administrators to create or delete any files on the system.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

TwinCAT OPC UA Server contains a relative path traversal vulnerability that allows authenticated administrators to create or delete arbitrary files on the system. This affects TF6100 and TS6100 versions before 4.3.48.0 and TcOpcUaServer versions below 3.2.0.194.

MitigationUpdate TwinCAT TF6100/TS6100 to version 4.3.48.0 or later, or TcOpcUaServer to version 3.2.0.194 or later. Coordinate update during planned maintenance window due to industrial environment sensitivity.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Tf6100 FirmwareOperating system
Affected:< 4.3.48.0
Ts6100 FirmwareOperating system
Affected:< 4.3.48.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed TwinCAT TF6100 or TS6100 firmware version
    Check the TwinCAT runtime or firmware version through the TwinCAT Engineering environment, Windows registry, or product documentation. Look for the TF6100 or TS6100 component version information.
    Affected if The installed version is below 4.3.48.0
  2. Identify installed TcOpcUaServer version
    Check the TcOpcUaServer component version through the Windows registry under the Beckhoff installation path, or through the TwinCAT OPC UA Server configuration interface.
    Affected if The installed version is below 3.2.0.194
  3. Verify OPC UA Server feature is enabled
    Check if the TwinCAT OPC UA Server is configured and running. This can be verified through the TwinCAT System Manager, Windows Services console, or by checking if the TcOpcUaServer.exe process is active.
    Affected if The OPC UA Server is actively running or configured on the system
  4. Confirm administrator authentication is configured
    Review the OPC UA Server authentication settings to determine if administrator accounts are enabled for OPC UA access. Check the OPC UA Server configuration files or management interface.
    Affected if Administrator authentication is enabled for the OPC UA Server (authenticated admins can exploit the path traversal)

A system is affected if it runs a vulnerable version of TF6100 or TS6100 (below 4.3.48.0) or TcOpcUaServer (below 3.2.0.194) with the OPC UA Server feature enabled and administrator authentication configured.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.3.48.0 or later
Fixed in 4.3.48.0
Interim mitigation

Update TwinCAT TF6100/TS6100 to version 4.3.48.0 or later, or TcOpcUaServer to version 3.2.0.194 or later. Coordinate update during planned maintenance window due to industrial environment sensitivity.

Recommended fix High confidence

TF6100 Firmware >= 4.3.48.0 | TS6100 Firmware >= 4.3.48.0 | TcOpcUaServer >= 3.2.0.194

  1. Identify the current TF6100 or TS6100 firmware version installed on the system
  2. Identify the current TcOpcUaServer version installed
  3. If TF6100 Firmware is below version 4.3.48.0, upgrade the TF6100 firmware to version 4.3.48.0 or later
  4. If TS6100 Firmware is below version 4.3.48.0, upgrade the TS6100 firmware to version 4.3.48.0 or later
  5. Alternatively, if using TcOpcUaServer, upgrade to version 3.2.0.194 or later
  6. After upgrading, verify the TwinCAT OPC UA Server is functioning correctly
  7. Test that the relative path traversal vulnerability is no longer present

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tf6100 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-34594 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data