Mitsubishi MELSEC iQ-F EtherNet/IP Module Flaws

Denial-of-service in Mitsubishi Electric MELSEC iQ-F Series FX5-ENET/IP Ethernet Modules (all versions) allows unauthenticated remote attackers to halt the module's communication function by flooding its Ethernet port with packets. The high packet rate overwhelms internal anomaly-detection processing and stops communications - a critical impact for the industrial control environments these PLCs operate in. No public exploit identified at time of analysis, but the CVSS 4.0 score of 8.7 reflects high availability impact in operational technology contexts.

Denial-of-service in Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP module (versions 1.000 and prior) allows a remote unauthenticated attacker to crash the device by rapidly opening many TCP connections, which trips an integer overflow in the EtherNet/IP connection-management logic and triggers improper memory access. No public exploit identified at time of analysis, but the CVSS 4.0 vector (AV:N/AC:L/PR:N/UI:N) and high availability impact make this a meaningful operational-technology (OT) concern for plants relying on the affected PLC module. Reported by the vendor and tracked in vendor PSIRT advisory 2026-002, JVN VU#97140216, and CISA ICS advisory ICSA-26-169-05.