CVE-2021-34594

highpriority · track · 26EPSS 0.011 · 66 %ileDEEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.13% (66th) EPSS

CVSS 8.5 · high

Is it mine?

12 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · beckhoff_psirt

EPSS · scored 2026-10-27

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedbeckhoff_psirt
Please update to a recent version of the affected product.
Mitigationbeckhoff_psirt
Consider restricting access to the nodes of the 'TcOpcUAServer' with the methods described by https://infosys.beckhoff.com/content/1033/tcopcuaserver/5930038411-1.html such that the administrative interface can only be accessed by administrative users of well known OPC UA clients.

cvss

Technical severity, 0–10. One row per scoring source.

8.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6–8.5

v2.08.5highAV:N/AC:L/Au:S/C:N/I:C/A:Cprimary · NVD / NIST USexploitability 8 · impact 9.2

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:Hprimary · NVD / NIST USexploitability 1.2 · impact 5.2

v3.16.5mediumAV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:Hsecondary · ENISA EU

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:Hsecondary · info@cert.vde.comexploitability 1.2 · impact 5.2

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:Hsecondary · Beckhoff PSIRT DE

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-22USprimaryCWE-23USCWE-23USCWE-23US

affected products (12)

Products and version ranges known to be affected.

Firmware 3.2.0.194 installed on TwinCAT OPC UA Server in TF6100 < 4.3.48.0all versionsfixedbeckhoff_psirtDE
Firmware 3.2.0.194 installed on TwinCAT OPC UA Server in TS6100 < 4.3.48.0all versionsfixedbeckhoff_psirtDE
Firmware <3.2.0.194 installed on TwinCAT OPC UA Server in TF6100 < 4.3.48.0all versionsbeckhoff_psirtDE
Firmware <3.2.0.194 installed on TwinCAT OPC UA Server in TS6100 < 4.3.48.0all versionsbeckhoff_psirtDE
Beckhoff Automation TwinCAT OPC UA ServerTF6100 → 4.3.48.0enisa_euvdEU
Beckhoff Automation TwinCAT OPC UA ServerTS6100 → 4.3.48.0enisa_euvdEU
Beckhoff Automation TwinCAT OPC UA ServerTcOpcUaServer version → 3.2.0.19423enisa_euvdEU
Beckhoff Automation GmbH & Co. KG TF6100≤ 4.3.48.0fstec_bduRU
Beckhoff Automation GmbH & Co. KG TS6100≤ 4.3.48.0fstec_bduRU
Beckhoff Automation GmbH & Co. KG TcOpcUaServer≤ 3.2.0.194fstec_bduRU
beckhoff tf6100 firmware< 4.3.48.0nvdUScpe:2.3:o:beckhoff:tf6100_firmware:*:*:*:*:*:*:*:*
beckhoff ts6100 firmware< 4.3.48.0nvdUScpe:2.3:o:beckhoff:ts6100_firmware:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

VDE-2021-051Beckhoff: Relative path traversal vulnerability through TwinCAT OPC UA Server2021-11-04csaf · beckhoff_psirtDE
Through specific nodes of the server configuration interface of the TwinCAT OPC UA Server administrators are able to remotely create and delete any files on the system which the server is running on, though this access should have been restricted to specific directories. In case that configuration interface is combined with not recommended settings to allow anonymous access via the TwinCAT OPC UA Server then this kind of file access is even possible for any unauthenticated user from remote.

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu beckhoff_psirt nvd NVD CVE.org MITRE

published 2021-11-04modified 2026-06-17

related (12,529)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2026-104286US	—OT critical	4.57% (92nd)	KEV	2026-10-01
An improper limitation of a pathname to a restricted directory ('path traversal') vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail…
CVE-2026-93616US	—OT critical	91.6% (100th)	KEV	2026-09-22
A directory traversal and file upload vulnerability allows an unauthenticated attacker to upload and execute arbitrary scripts on Check Point Management Server.
CVE-2026-85706US	—OT critical	97.4% (100th)	KEV	2026-09-12
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.7 before 18.11.12, 19.0 before 19.0.9, 19.1 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2…
CVE-2026-66384US	—OT critical	0.66% (52nd)	KEV	2026-08-12
An authenticated user may write data outside the intended Docker cache path under specific remote-repository conditions.
CVE-2026-59310US	—OT critical	2.56% (85th)	KEV	2026-07-30
VMware vCenter contains a directory traversal vulnerability in the Syslog server. A malicious actor with network access to vCenter may exploit this issue to execute arbitrary code.

+12524 more

references (5)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan