OpenPLC Runtime v3 Path Traversal in Structured Text FILE Directive Leading to Arbitrary File Write

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-71268
StatePUBLISHED
AssignerTuranSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 13:24:51 UTC
Updated2026-08-05 16:17:06 UTC
DescriptionOpenPLC 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.

Risk And Classification

Primary CVSS: v3.1 9.9 CRITICAL from 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

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

Problem Types: CWE-22 | CWE-22 CWE-22

VersionSourceTypeScoreSeverityVector
3.1309f9ea4-e3e9-4c6c-b79d-e8eb01244f2cSecondary9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNADECLARED9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Thiagoralves OpenPLC V3 affected * custom Not specified

References

ReferenceSourceLinkTags
github.com/thiagoralves/OpenPLC_v3/blob/master/webserver/openplc.py 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c github.com
github.com/thiagoralves/OpenPLC_v3 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Alibek Baxtiyorov (en)

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