Johnson Controls iSTAR Ultra

1. EXECUTIVE SUMMARY

CVSS v4 8.7
ATTENTION: Exploitable remotely/low attack complexity
Vendor: Johnson Controls
Equipment: iSTAR Ultra, iSTAR Ultra SE, iSTAR Ultra G2, iSTAR Ultra G2 SE, iSTAR Edge G2, iSTAR Ultra LT
Vulnerabilities: OS Command Injection

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to modify firmware and gain full access to the device.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of iSTAR Ultra and iSTAR Edge door controllers are affected:

iSTAR Ultra: Versions prior to 6.9.7.CU01
iSTAR Ultra SE: Versions prior to 6.9.7.CU01
iSTAR Ultra LT: Versions prior to 6.9.7.CU01
iSTAR Ultra G2: Versions prior to 6.9.3
iSTAR Ultra G2 SE: Versions prior to 6.9.3
iSTAR Edge G2: Versions prior to 6.9.3

3.2 VULNERABILITY OVERVIEW

3.2.1 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN OS COMMAND (‘OS COMMAND INJECTION’) CWE-78

Johnson Controls iSTAR Ultra, Ultra SE, Ultra LT versions prior to 6.9.7.CU01 and Ultra G2, Ultra G2 SE, Edge G2 versions prior to 6.9.3 are vulnerable to OS Command Injection under certain circumstances that could allow an attacker full control of the device.

CVE-2025-43873 has been assigned to this vulnerability. A CVSS v3.1 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2025-43873. A base score of 8.7 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).

3.2.2 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN OS COMMAND (‘OS COMMAND INJECTION’) CWE-78

CVE-2025-43874 has been assigned to this vulnerability. A CVSS v3.1 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2025-43874. A base score of 8.7 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Commercial Facilities, Government Services and Facilities, Transportation Systems, Energy
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Ireland

3.4 RESEARCHER

Reid Wightman of Dragos reported these vulnerabilities to CISA.

4. MITIGATIONS

Johnson Controls recommends users take the following actions:

Upgrade iSTAR Ultra, iSTAR Ultra SE, iStar Ultra LT to version 6.9.7.CU01 or greater.
Upgrade iSTAR Ultra G2, iSTAR Ultra G2 SE, iSTAR Edge G2 to version 6.9.3 or greater.
For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2025-11 and JCI-PSA-2025-13.
Johnson Controls recommends taking steps to minimize risks to all building automation systems in alignment with CISA’s guidance.
Further ICS security notices and product security guidance are located at Johnson Controls product security website.
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

For more information please contact Johnson Controls Global Product Security or visit their Cybersecurity page.

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, such as:

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.

No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.

5. UPDATE HISTORY

December 11, 2025: Initial Publication

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