CVE intelligence and bounded remediation

CVE-2021-34594 — Beckhoff Tf6100 Firmware security vulnerability

High CVSS 8.5

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.

Severity
High
CVSS
8.5 (2.0)
Published
2021-11-04
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-23, CWE-22

Affected products

  • beckhoff / tf6100_firmware
  • beckhoff / ts6100_firmware

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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