CVE-2020-5594: Mitsubishielectric Melsec-Fx Firmware

Critical severity, CVSS 9.8. EPSS: 1.3% chance of exploitation in the next 30 days.

Mitsubishi Electric MELSEC iQ-R, iQ-F, Q, L, and FX series CPU modules all versions contain a vulnerability that allows cleartext transmission of sensitive information between CPU modules and GX Works3 and/or GX Works2 via unspecified vectors.

Affected products

• Mitsubishielectric Melsec-Fx Firmware: any version
• Mitsubishielectric Melsec-L Firmware: any version
• Mitsubishielectric Melsec-Q Firmware: any version
• Mitsubishielectric Melsec Iq-F Firmware: any version
• Mitsubishielectric Melsec Iq-R Firmware: any version

Published 2020-06-23. Last modified 2026-06-17.