CVE-2025-61690 is a high-severity buffer underflow vulnerability identified in KEYENCE CORPORATION's KV STUDIO software, specifically affecting versions 12.23 and earlier. KV STUDIO is an engineering software product used for programming and configuring KEYENCE programmable logic controllers (PLCs), which are critical components in industrial automation and control systems. The vulnerability arises from improper handling of specially crafted files that the software processes. When such a maliciously crafted file is opened or imported into KV STUDIO, it triggers a buffer underwrite condition—also known as buffer underflow—where the program writes data before the beginning of a buffer. This memory corruption can lead to arbitrary code execution within the context of the user running the software. The CVSS v3.1 base score of 7.8 reflects a high severity rating, with the vector indicating that the attack requires local access (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but does require user interaction (UI:R). The impact on confidentiality, integrity, and availability is high, meaning an attacker could potentially execute malicious code, compromise system integrity, and disrupt operations. No known exploits are currently reported in the wild, and no patches or mitigations have been explicitly linked yet. Given the nature of KV STUDIO as a PLC programming tool, exploitation could have serious consequences in industrial environments where these controllers manage critical infrastructure or manufacturing processes.

For European organizations, the impact of this vulnerability could be significant, especially for those operating in industrial sectors such as manufacturing, automotive, energy, and utilities where KEYENCE PLCs and KV STUDIO are deployed. Successful exploitation could allow attackers to execute arbitrary code on engineering workstations, potentially leading to unauthorized changes in PLC programming logic. This could cause operational disruptions, safety hazards, data breaches, or sabotage of industrial processes. The high confidentiality impact means sensitive design and operational data could be exposed. Integrity impact could result in manipulated control logic causing physical damage or downtime. Availability impact could disrupt production lines or critical infrastructure services. Given the increasing targeting of industrial control systems by cyber adversaries, European organizations using KV STUDIO must consider this vulnerability a serious risk to their operational technology (OT) environments.

1. Immediate isolation of engineering workstations running KV STUDIO from untrusted networks to reduce exposure. 2. Restrict file sources strictly to trusted and verified origins; do not open files from unknown or untrusted parties. 3. Implement strict user training and awareness to prevent inadvertent opening of malicious files, emphasizing the risk of social engineering. 4. Monitor vendor communications closely for official patches or updates addressing CVE-2025-61690 and apply them promptly upon release. 5. Employ application whitelisting and endpoint protection solutions capable of detecting anomalous behavior related to KV STUDIO processes. 6. Conduct regular backups of PLC programs and configuration files to enable recovery in case of compromise. 7. Consider network segmentation to separate OT engineering environments from corporate IT networks to limit lateral movement. 8. Perform vulnerability scanning and penetration testing focused on OT environments to identify and remediate related weaknesses. These steps go beyond generic advice by focusing on operational technology context and the specific attack vector involving specially crafted files.