VulnerabilityPublished 11 Jun 2025

CVE-2025-26383: Johnson Controls iSTAR Configuration Utility (ICU) · Use of Uninitialized Variable

Affects Johnson Controls iSTAR Configuration Utility (ICU)Source CVE Database V5

Not known to be exploited · CVSS 6.3 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

6.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:N/SA:N

Attack Vector: Adjacent
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable system is bound to a protocol stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared proximity (e.g., Bluetooth, NFC, or IEEE 802.11) or logical network (e.g., local IP subnet), or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN within an administrative network zone).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Johnson Controls iSTAR Configuration Utility (ICU)	Affected =0	Fixed in–

AI-suggested

European organizations should implement the following specific mitigation measures: 1) Restrict network access to the ICU tool by segmenting the network and applying strict firewall rules to limit access only to authorized administrators and management systems. 2) Monitor network traffic for unusual access patterns or data exfiltration attempts from systems running the ICU tool. 3) Conduct an inventory of all systems running the iSTAR Configuration Utility and isolate them from less trusted network zones. 4) Apply principle of least privilege to user accounts managing the ICU tool to minimize potential exposure. 6) Engage with Johnson Controls for updates on patches or workarounds and plan for prompt deployment once available. 7) Educate IT and security teams about the vulnerability specifics to ensure rapid identification and response to any suspicious activity related to the ICU tool. 8) Regularly audit and review access control configurations to detect unauthorized changes that could be facilitated by leaked credentials or configuration data.

Description

The iSTAR Configuration Utility (ICU) tool leaks memory, which could result in the unintended exposure of unauthorized data from the Windows PC that ICU is running on.

Impact

For European organizations, especially those in critical infrastructure sectors such as government buildings, transportation hubs, healthcare facilities, and corporate offices that utilize Johnson Controls iSTAR access control systems, this vulnerability poses a risk of unauthorized data exposure. The leaked memory could contain sensitive configuration data or credentials that attackers might leverage to escalate privileges or move laterally within the network. Although the vulnerability does not directly allow system compromise or denial of service, the confidentiality breach could facilitate further attacks against physical security systems or corporate networks. The requirement for adjacent network access limits remote exploitation but does not eliminate risk within internal networks or compromised segments. Organizations with large deployments of Johnson Controls access control solutions may face increased risk due to the potential for aggregated sensitive data exposure. Additionally, the high scope impact suggests that exploitation could affect multiple components or systems interconnected with the ICU tool, amplifying the potential damage. The absence of known exploits in the wild provides a window for mitigation, but organizations should act proactively given the strategic importance of physical security systems in Europe.

CWE-457Use of Uninitialized Variable (opens in a new tab)
Variant weaknessLikelihood of exploit: High
The code uses a variable that has not been initialized, leading to unpredictable or unintended results.
Implementation · Attack Surface Reduction
Ensure that critical variables are initialized before first use.
Build and Compilation · Compilation or Build Hardening
Most compilers will complain about the use of uninitialized variables if warnings are turned on.
Implementation · Operation
When using a language that does not require explicit declaration of variables, run or compile the software in a mode that reports undeclared or unknown variables. This may indicate the presence of a typographic error in the variable's name.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Jul 2025, 08:16 UTC

WeaknessesCWE-457

Technical details

References

Community reviews

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