CVE-2025-66604 identifies a vulnerability in Yokogawa Electric Corporation's FAST/TOOLS software suite, versions R9.01 through R10.04, which are used in industrial automation and control systems. The vulnerability is categorized under CWE-319, indicating cleartext transmission of sensitive information. Specifically, the software's web interface exposes the library version information openly on web pages. This exposure can be leveraged by attackers to gain intelligence about the software environment, potentially facilitating targeted attacks such as exploiting known vulnerabilities in specific library versions or crafting social engineering attacks. The CVSS 4.0 base score is 2.1, reflecting a low severity due to factors including network attack vector, high attack complexity, partial user interaction, and low confidentiality impact. The vulnerability does not affect integrity or availability and does not require privileges or authentication. No patches or exploits are currently documented, but the information disclosure could be a reconnaissance step in multi-stage attacks. Given the critical nature of industrial control systems where FAST/TOOLS is deployed, even low-severity vulnerabilities warrant attention to prevent escalation. The vulnerability highlights the importance of securing web interfaces and minimizing information leakage in operational technology environments.

For European organizations, especially those operating critical infrastructure and industrial control systems using Yokogawa FAST/TOOLS, this vulnerability poses a limited but non-negligible risk. The disclosure of library version information can aid attackers in reconnaissance, increasing the likelihood of successful targeted attacks if other vulnerabilities exist. While the direct impact on confidentiality is low and there is no immediate threat to system integrity or availability, the vulnerability could be exploited as part of a broader attack chain. This is particularly relevant for sectors such as energy, manufacturing, and utilities, where Yokogawa products are commonly deployed. The exposure could lead to increased risk of cyber espionage or sabotage attempts. However, the high attack complexity and requirement for user interaction reduce the immediacy of the threat. Organizations with stringent network segmentation and monitoring may further mitigate risk. Nonetheless, awareness and proactive mitigation are important to maintain operational security and prevent potential escalation.

To mitigate CVE-2025-66604, European organizations should implement the following specific measures: 1) Restrict access to FAST/TOOLS web interfaces to trusted networks and users only, employing network segmentation and firewall rules to limit exposure. 2) Configure web servers and applications to suppress or obfuscate version information and other sensitive metadata in HTTP responses and web pages. 3) Enforce the use of encrypted communication protocols such as HTTPS with strong TLS configurations to prevent interception of transmitted data. 4) Conduct regular security audits and vulnerability assessments focusing on information leakage and web interface security. 5) Monitor network traffic and logs for unusual access patterns or reconnaissance activity targeting FAST/TOOLS components. 6) Engage with Yokogawa Electric Corporation for updates or patches addressing this vulnerability and apply them promptly when available. 7) Train operational technology personnel on secure configuration practices and the risks of information disclosure. These targeted actions go beyond generic advice by focusing on reducing information exposure and strengthening perimeter defenses specific to industrial control systems.