Description
OpenPLC Runtime v3's compile_program() function (webserver/openplc.py) parses `(*FILE:path content*)` directives from uploaded Structured Text (.st) program files and writes the referenced content to `os.path.join('./core', file_path)` with no validation that file_path stays within the ./core directory. A crafted .st file containing a directive such as `(*FILE:../../../etc/cron.d/x * * * * root <command>*)` writes attacker-controlled content to an arbitrary filesystem path, enabling remote code execution (e.g. via cron or SSH authorized_keys). A path-validation function, validate_file_path(), exists elsewhere in the codebase (webserver/credentials.py) but is never invoked from compile_program(), leaving the sink unprotected. OpenPLC additionally ships with hardcoded default credentials (openplc:openplc), lowering the practical bar for exploitation.
Published: 2026-08-05
Score: 9.9 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Wed, 05 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Description OpenPLC Runtime v3's compile_program() function (webserver/openplc.py) parses `(*FILE:path content*)` directives from uploaded Structured Text (.st) program files and writes the referenced content to `os.path.join('./core', file_path)` with no validation that file_path stays within the ./core directory. A crafted .st file containing a directive such as `(*FILE:../../../etc/cron.d/x * * * * root <command>*)` writes attacker-controlled content to an arbitrary filesystem path, enabling remote code execution (e.g. via cron or SSH authorized_keys). A path-validation function, validate_file_path(), exists elsewhere in the codebase (webserver/credentials.py) but is never invoked from compile_program(), leaving the sink unprotected. OpenPLC additionally ships with hardcoded default credentials (openplc:openplc), lowering the practical bar for exploitation.
Title OpenPLC Runtime v3 Path Traversal in Structured Text FILE Directive Leading to Arbitrary File Write
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 9.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: TuranSec

Published:

Updated: 2026-08-05T12:52:34.216Z

Reserved: 2026-08-05T12:23:34.967Z

Link: CVE-2026-71268

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses