Vulnerability · Published Aug 5, 2026 · Assigned by TuranSec

CVE-2026-71268OpenPLC Runtime v3 Path Traversal in Structured Text FILE Directive Leading to Arbitrary File Write

Critical 9.9

In plain English

A critical-severity path traversal in OpenPLC_v3 from thiagoralves. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)9.9Critical

Exploit odds (30 days)0.6%top 52.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

OpenPLC Runtime v3's compile_program function (webserver/openplc.py) parses directives from uploaded Structured Text (.st) program files and writes the referenced content to with no validation that file_path stays within the ./core directory. 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.

Affected products (as reported)

Vendor	Product	Versions
thiagoralves	OpenPLC_v3	0 – through *

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/thiagoralves/OpenPLC_v3 third-party-advisory
https://github.com/thiagoralves/OpenPLC_v3/blob/master/webserver/openplc.py third-party-advisory