Mitsubishi Electric’s MELSEC iQ-F Series FX5-EIP EtherNet/IP module suffers from an integer overflow or wraparound in its EtherNet/IP function, allowing a remote attacker to trigger a denial‑of‑service by rapidly opening a large number of TCP connections. The overflow causes an inconsistency in the module’s internal connection management and leads to improper memory access, interrupting normal operation without compromising confidentiality or integrity.

The flaw affects Mitsubishi Electric MELSEC iQ‑F Series FX5‑EIP EtherNet/IP Module FX5‑EIP, versions 1.000 and earlier. The vulnerability is specific to this product line and version family.

The CVSS score of 8.7 indicates high severity. EPSS is not available, and the vulnerability is not listed in CISA KEV. Attacks are likely conducted remotely over the network by a malicious actor with no local or administrative privileges, leveraging the EtherNet/IP protocol to flood the module with connections. Once the integer overflows, the device experiences a service outage due to improper memory handling.