CVE-2025-10089 is a vulnerability classified under CWE-427 (Uncontrolled Search Path Element) affecting all versions of Mitsubishi Electric Corporation's MILCO.S Setting Application and its variants, which are used for lighting control systems. The vulnerability allows a local attacker to execute arbitrary malicious code during the installation process by exploiting the way the installer loads DLLs. Specifically, the installer does not securely handle the search path for DLLs, allowing an attacker to place a malicious DLL in a location that the installer will load instead of the legitimate one. This DLL hijacking attack vector requires the attacker to have local access to the system and the ability to influence the installer's environment, such as placing files in the installer's directory or a directory in the DLL search path. The vulnerability does not affect the application after installation, only the installer execution phase. The risk is mitigated if the installer executable's digital signature shows the signer name "Mitsubishi Electric Lighting," indicating a fixed version. Users who download the installer directly from Mitsubishi Electric's official website receive a signed and safe installer. The CVSS v3.1 base score is 7.0 (high severity), reflecting local attack vector, high attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. No known exploits have been reported in the wild as of now. The vulnerability highlights the importance of secure DLL loading practices and digital signature verification in software installation processes.

For European organizations, especially those in industrial automation, smart building management, and lighting control sectors, this vulnerability poses a significant risk during the installation or update of the MILCO.S Setting Application. Successful exploitation could lead to arbitrary code execution with the privileges of the user running the installer, potentially allowing attackers to install persistent malware, disrupt lighting control systems, or pivot to other parts of the network. This could impact operational continuity, safety, and data confidentiality. Since the vulnerability requires local access and user interaction, the threat is higher in environments where installers are distributed via removable media or untrusted networks. The impact is mitigated if organizations enforce strict software sourcing policies and verify digital signatures. However, failure to do so could lead to compromise of critical building infrastructure, affecting energy management and security systems. The absence of known exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability is public.

1. Always obtain the MILCO.S Setting Application installer directly from Mitsubishi Electric's official website to ensure the installer is digitally signed and free from tampering. 2. Before running the installer, verify the digital signature on "MILCO.S Lighting Control.exe" to confirm the signer name is "Mitsubishi Electric Lighting." 3. Restrict installer execution privileges to trusted administrators and limit local user permissions to prevent unauthorized installer execution. 4. Avoid installing or updating the application from removable media or untrusted network shares where malicious DLLs could be introduced. 5. Monitor and control the directories included in the DLL search path during installation to prevent DLL hijacking. 6. Implement application whitelisting and endpoint protection solutions that can detect and block unauthorized DLL loading or suspicious installer behavior. 7. Once Mitsubishi Electric releases official patches or updated installers addressing this vulnerability, apply them promptly. 8. Educate IT and operational technology staff about the risks of installing software from unverified sources and the importance of digital signature verification.