Critical PLC Vulnerability Enables Arbitrary RPCs in Contemporary Controls BASC 20T
Summary
CISA published ICS Advisory ICSA-26-099-01 disclosing a critical vulnerability (CVE-2025-13926, CVSS 9.8) in Contemporary Controls BASControl20 version 3.1 PLCs. The flaw allows remote attackers to forge network packets and execute arbitrary Remote Procedure Calls, potentially enabling full device compromise. Affected sectors include Energy, Critical Manufacturing, and Commercial Facilities.
What changed
CISA published a critical ICS advisory identifying CVE-2025-13926 in Contemporary Controls BASControl20 version 3.1 PLCs (BASC 20T). The vulnerability (CVSS 9.8, CWE-807) allows attackers who can sniff network traffic to forge packets and make arbitrary RPCs to the PLC, potentially enabling full device compromise, reconfiguration, file transfers, and enumeration of PLC functionality.
Critical infrastructure operators in Energy, Critical Manufacturing, and Commercial Facilities sectors must assess exposure to this obsolete product. Since Contemporary Controls has not issued a patch (product is obsolete), affected organizations should immediately isolate vulnerable devices from internet-facing and business networks, implement defensive measures such as VPNs and firewalls, and contact the vendor for guidance. Organizations should perform impact analysis and risk assessment to determine appropriate compensating controls.
What to do next
- Identify and isolate all BASControl20 3.1 PLCs from network exposure
- Contact Contemporary Controls for mitigation guidance since the product is obsolete
- Implement compensating controls such as VPNs or network segmentation if remote access is required
Archived snapshot
Apr 9, 2026GovPing captured this document from the original source. If the source has since changed or been removed, this is the text as it existed at that time.
ICS Advisory
Contemporary Controls BASC 20T
Release Date
April 09, 2026
Alert Code ICSA-26-099-01 Related topics: Industrial Control System Vulnerabilities, Industrial Control Systems View CSAF
Summary
Successful exploitation of this vulnerability could allow an attacker to enumerate the functionality of each component associated with the PLC, reconfigure, rename, delete, perform file transfers, and make remote procedure calls.
The following versions of Contemporary Controls BASC 20T are affected:
- BASControl20 3.1 (CVE-2025-13926)
| CVSS | Vendor | Equipment | Vulnerabilities |
|---|---|---|---|
| v3 9.8 | Contemporary Controls Sedona Alliance | Contemporary Controls BASC 20T | Reliance on Untrusted Inputs in a Security Decision |
Background
- Critical Infrastructure Sectors: Commercial Facilities, Critical Manufacturing, Energy
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: United States
Vulnerabilities
CVE-2025-13926
An attacker could use data obtained by sniffing the network traffic to forge packets in order to make arbitrary requests to Contemporary Controls BASC 20T.
Affected Products
Contemporary Controls BASC 20T
Vendor:
Contemporary Controls Sedona Alliance Product Version:
Contemporary Controls Sedona Alliance BASControl20: 3.1 Product Status:
known_affected
Remediations
Mitigation
According to Contemporary Controls, the BASC-20T is an obsolete product. It is recommended that users of the affected product contact Contemporary Controls for additional information.
https://www.ccontrols.com/support/contacttech.htm
Relevant CWE: CWE-807 Reliance on Untrusted Inputs in a Security Decision
Metrics
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Acknowledgments
- Joseph Fields of Naval Information Warfare Center Pacific 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: 2026-04-09
| Date | Revision | Summary |
|---|---|---|
| 2026-04-09 | 1 | Initial Publication |
Legal Notice and Terms of Use
This product is provided subject to this Notification and this Privacy & Use policy.
Tags
Sector: Commercial Facilities Sector, Critical Manufacturing Sector, Energy Sector Topics: Industrial Control System Vulnerabilities, Industrial Control Systems
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