OpenPLC v3
All CISA Advisories, CISA, July 9, 2026
Summary
Successful exploitation of this vulnerability could allow an authenticated attacker to write arbitrary files to the filesystem and escalate this into arbitrary native code execution through the normal OpenPLC program compilation process, potentially resulting in code execution as the OpenPLC runtime user.
The following versions of OpenPLC v3 are affected:
- OpenPLC v3
| CVSS | Vendor | Equipment | Vulnerabilities |
|---|---|---|---|
| v3 9.9 | OpenPLC | OpenPLC v3 | External Control of File Name or Path |
Background
- Critical Infrastructure Sectors: Critical Manufacturing, Energy, Transportation Systems, Water and Wastewater
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: United States
Vulnerabilities
CVE-2026-14480
OpenPLC Runtime v3 contains an authenticated arbitrary file write vulnerability in the legacy web UI program‑upload workflow. The application stores an attacker‑supplied filename (prog_file) directly into the Programs.File database field and later uses this value as the destination path for an uploaded file without validating or restricting the path. Because Python os.path.join() honors attacker‑controlled absolute paths, an authenticated user can write arbitrary files anywhere writable by the OpenPLC webserver process. In the default build pipeline, all C++ source files within the OpenPLC runtime core directory are automatically compiled into the executable runtime binary. By writing a malicious .cpp file into this directory, an authenticated attacker can escalate the arbitrary file write into arbitrary native code execution when the operator triggers a normal program compilation and runtime start.
Affected Products
OpenPLC v3
OpenPLC
OpenPLC OpenPLC: v3
known_affected
Remediations
Vendor fix
OpenPLC recommends users upgrade to OpenPLC v4 as OpenPLC v3 is end-of-life and is no longer receiving patches, bug fixes, or security updates.
Relevant CWE: CWE-73 External Control of File Name or Path
Metrics
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 9.9 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| 4.0 | 8.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
Acknowledgments
- Grady DeRosa reported this vulnerability to CISA
Legal Notice and Terms of Use
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
CISA also recommends users take the following measures to protect themselves from social engineering attacks:
Do not click web links or open attachments in unsolicited email messages.
Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
Revision History
- Initial Release Date: 2026-07-09
| Date | Revision | Summary |
|---|---|---|
| 2026-07-09 | 1 | Initial Publication |
