CVE-2026-71268
CriticalCVSS 9.9Exploitation Probability (EPSS)
Low risk47th percentile - higher than 47% of all known CVEs
Summary
OpenPLC Runtime v3's compile_program function parses directives from uploaded Structured Text (.st) files and writes referenced content without validating that the file path stays within the ./core directory. A path-validation function exists but is never invoked from compile_program.
Risk Assessment
An attacker can upload a malicious .st file that causes file writes outside the allowed directory, potentially leading to overwriting critical system files or code execution.
Recommendation
Integrate path validation into compile_program to ensure files are only written within the allowed directory. Also update to the latest OpenPLC version.
Other vulnerabilities in OpenPLC Runtime
See all- CVE-2026-14480Critical
OpenPLC Runtime v3 has an authenticated arbitrary file write vulnerability in the legacy web UI program upload workflow. An attacker can supply an arbitrary filename stored in the database and used as the destination path without validation, allowing file writes anywhere writable by the webserver process.
- CVE-2025-34226High
OpenPLC Runtime v3 contains an input validation flaw in the /upload-program-action endpoint: the epoch_time field supplied during program uploads is not validated and can be crafted to induce corruption of the programs database. After a successful malformed upload the runtime continues to operate until a restart; on restart the runtime can fail to start because of corrupted database entries, resulting in persistent denial of service requiring complete rebase of the product to recover. This vulnerability was remediated by commit 095ee09.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS