CVE-2025-26382 is a stack-based buffer overflow vulnerability identified in the Johnson Controls iSTAR Configuration Utility (ICU). This utility is used to configure and manage iSTAR access control systems, which are widely deployed in physical security environments. The vulnerability arises under certain conditions where the ICU improperly handles input data, leading to a buffer overflow on the stack. This type of vulnerability (CWE-121) can allow an attacker to overwrite adjacent memory on the stack, potentially leading to arbitrary code execution, denial of service, or system crashes. The flaw exists in the ICU software, which is a critical tool for configuring access control hardware, and may be exploited if an attacker can supply specially crafted input to the utility. Although no public exploits are currently known in the wild and no patches have been released as of the publication date, the vulnerability poses a significant risk due to the potential for privilege escalation or disruption of physical security management. The affected versions are not explicitly detailed beyond version '0', suggesting the issue may be present in initial or early releases of the ICU software. The vulnerability was reserved in early February 2025 and publicly disclosed in April 2025, with the vendor Johnson Controls being the assigner. The lack of a CVSS score requires an independent severity assessment based on the nature of the vulnerability and its potential impact.

For European organizations, the impact of this vulnerability could be substantial, particularly for those relying on Johnson Controls' iSTAR access control systems to secure physical premises such as corporate offices, data centers, government buildings, and critical infrastructure. Exploitation could allow attackers to execute arbitrary code within the configuration utility environment, potentially leading to unauthorized changes in access control configurations, disabling of security mechanisms, or disruption of physical security operations. This could result in unauthorized physical access, data breaches, or operational downtime. Given the integration of physical security with IT security in many organizations, a successful exploit could also serve as a pivot point for further network intrusion. The medium severity rating reflects the need for attacker proximity or access to the configuration utility, which may require local or network access depending on deployment. However, the absence of known exploits and patches means organizations must proactively assess their exposure and implement mitigations to prevent exploitation.

1. Restrict access to the iSTAR Configuration Utility to trusted administrators only, enforcing strict access controls and network segmentation to limit exposure. 2. Monitor and audit usage of the ICU tool to detect any anomalous or unauthorized activity that could indicate exploitation attempts. 3. Employ application whitelisting and endpoint protection solutions on systems running the ICU to prevent execution of unauthorized code. 4. Engage with Johnson Controls for updates and patches; apply any forthcoming security updates promptly once available. 5. Consider isolating the configuration environment from general user networks, possibly using dedicated management VLANs or jump servers with hardened security. 6. Conduct internal security assessments and penetration testing focusing on the ICU deployment to identify potential exploitation vectors. 7. Educate administrators on the risks of buffer overflow vulnerabilities and encourage cautious handling of input data within the configuration utility.