Mitsubishi Electric MELSEC iQ-F Series

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1. EXECUTIVE SUMMARY CVSS v3 5.3 ATTENTION: Exploitable remotely/low attack complexity Vendor: Mitsubishi Electric Equipment: MELSEC iQ-F Series Vulnerability: Improper Validation of Specified Quantity in Input
2. RISK EVALUATION Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition on the product.
3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following versions of Mitsubishi Electric MELSEC iQ-F Series are affected: FX5U-32MT/ES: All versions FX5U-32MT/DS: All versions FX5U-32MT/ESS: All versions FX5U-32MT/DSS: All versions FX5U-64MT/ES: All versions FX5U-64MT/DS: All versions FX5U-64MT/ESS: All versions FX5U-64MT/DSS: All versions FX5U-80MT/ES: All versions FX5U-80MT/DS: All versions FX5U-80MT/ESS: All versions FX5U-80MT/DSS: All versions FX5U-32MR/ES: All versions FX5U-32MR/DS: All versions FX5U-64MR/ES: All versions FX5U-64MR/DS: All versions FX5U-80MR/ES: All versions FX5U-80MR/DS: All versions FX5UC-32MT/D: All versions FX5UC-32MT/DSS: All versions FX5UC-64MT/D: All versions FX5UC-64MT/DSS: All versions FX5UC-96MT/D: All versions FX5UC-96MT/DSS: All versions FX5UC-32MT/DS-TS: All versions FX5UC-32MT/DSS-TS: All versions FX5UC-32MR/DS-TS: All versions FX5UJ-24MT/ES: All versions FX5UJ-24MT/DS: All versions FX5UJ-24MT/ESS: All versions FX5UJ-24MT/DSS: All versions FX5UJ-40MT/ES: All versions FX5UJ-40MT/DS: All versions FX5UJ-40MT/ESS: All versions FX5UJ-40MT/DSS: All versions FX5UJ-60MT/ES: All versions FX5UJ-60MT/DS: All versions FX5UJ-60MT/ESS: All versions FX5UJ-60MT/DSS: All versions FX5UJ-24MR/ES: All versions FX5UJ-24MR/DS: All versions FX5UJ-40MR/ES: All versions FX5UJ-40MR/DS: All versions FX5UJ-60MR/ES: All versions FX5UJ-60MR/DS: All versions FX5UJ-24MR/ES-A: All versions FX5UJ-24MT/ES-A: All versions FX5UJ-40MR/ES-A: All versions FX5UJ-40MT/ES-A: All versions FX5UJ-60MR/ES-A: All versions FX5UJ-60MT/ES-A: All versions FX5S-30MT/ES: All versions FX5S-30MT/DS: All versions FX5S-30MT/ESS: All versions FX5S-30MT/DSS: All versions FX5S-40MT/ES: All versions FX5S-40MT/DS: All versions FX5S-40MT/ESS: All versions FX5S-40MT/DSS: All versions FX5S-60MT/ES: All versions FX5S-60MT/DS: All versions FX5S-60MT/ESS: All versions FX5S-60MT/DSS: All versions FX5S-80MT/ES: All versions FX5S-80MT/DS: All versions FX5S-80MT/ESS: All versions FX5S-80MT/DSS: All versions FX5S-30MR/ES: All versions FX5S-30MR/DS: All versions FX5S-40MR/ES: All versions FX5S-40MR/DS: All versions FX5S-60MR/ES: All versions FX5S-60MR/DS: All versions FX5S-80MR/ES: All versions FX5S-80MR/DS: All versions FX5S-30MR/ES-A: All versions FX5S-30MT/ES-A: All versions FX5S-40MR/ES-A: All versions FX5S-40MT/ES-A: All versions FX5S-60MR/ES-A: All versions FX5S-60MT/ES-A: All versions FX5S-80MR/ES-A: All versions FX5S-80MT/ES-A: All versions 3.2 VULNERABILITY OVERVIEW 3.2.1 IMPROPER VALIDATION OF SPECIFIED QUANTITY IN INPUT CWE-1284 A denial-of-service (DoS) vulnerability exists in the TCP communication function on the MELSEC iQ-F Series CPU module. A remote attacker may be able to disconnect the connection by sending specially crafted TCP packets to cause a denial-of-service (DoS) condition on the products (CVE-2025-10259). There is no impact on connections other than the attacked one. CVE-2025-10259 has been assigned to this vulnerability. A CVSS v3.1 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L). 3.3 BACKGROUND CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing COUNTRIES/AREAS DEPLOYED: Worldwide COMPANY HEADQUARTERS LOCATION: Japan 3.4 RESEARCHER Qian Zou, Ke Xu, Xuewei Feng, Qi Li, Xueying Li, and Gang Jin from Zhongguancun Laboratory and Tsinghua University reported this vulnerability to Mitsubishi Electric.
4. MITIGATIONS Mitsubishi Electric recommends that users take the following mitigation measures to minimize the risk of exploiting this vulnerability: Use a virtual private network (VPN) to encrypt the communication when Internet access is required. Restrict physical access to the affected products and the LAN that is connected by them. For more information, see Mitsubishi Electric Advisory 2025-014. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies. Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents. No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
5. UPDATE HISTORY November 13, 2025: Initial Republication of Mitsubishi Electric Advisory 2025-014