Contemporary Controls BASC 20T

Summary

CISA published an advisory (ICSA-26-099-01) documenting a critical vulnerability (CVE-2025-13926) in Contemporary Controls BASC 20T programmable logic controllers affecting BASControl20 version 3.1. The flaw, rooted in reliance on untrusted network inputs (CWE-807), allows unauthenticated remote attackers to forge packets and execute arbitrary commands including enumeration, reconfiguration, deletion, and file transfer. While Contemporary Controls has designated the product obsolete, the vulnerability carries a CVSS 3.1 base score of 9.8 (critical severity) and impacts critical infrastructure sectors worldwide; no active public exploitation has been reported.

Full text

ICS Advisory Contemporary Controls BASC 20T Release DateApril 09, 2026 Alert CodeICSA-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 Expand All + 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. View CVE Details 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 MitigationAccording 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 Please share your thoughts We recently updated our anonymous product survey; we welcome your feedback. Related Advisories Apr 09, 2026 ICS Advisory | ICSA-26-099-02 GPL Odorizers GPL750 Apr 07, 2026 ICS Advisory | ICSA-26-097-01 Mitsubishi Electric GENESIS64 and ICONICS Suite products Apr 02, 2026 ICS Advisory | ICSA-26-092-01 Siemens SICAM 8 Products Apr 02, 2026 ICS Advisory | ICSA-26-092-02 Yokogawa CENTUM VP

Indicators of Compromise

• cve — CVE-2025-13926

Entities