LiveThreat Vulnerability Brief — Mitsubishi Electric MELSEC iQ‑F Series EtherNet/IP Module DoS Vulnerabilities (CVE‑2026‑1874, CVE‑2026‑1875, CVE‑2026‑1876)
What It Is — Three newly disclosed CVEs affect Mitsubishi Electric’s MELSEC iQ‑F Series EtherNet/IP and Ethernet modules. The flaws stem from an always‑incorrect control‑flow implementation and improper resource shutdown, enabling a remote attacker to flood the device with crafted UDP packets and trigger a denial‑of‑service (DoS). Exploitability — No public exploit or proof‑of‑concept has been observed, but the attack requires only network access; CVSS v3.1 base score 7.5 (High).
Affected Products — Mitsubishi Electric MELSEC iQ‑F Series FX5‑ENET/IP Ethernet Module (firmware ≤ 1.106) and FX5‑EIP EtherNet/IP Module (all firmware).
TPRM Impact — These PLC‑level modules are widely deployed in critical manufacturing lines. A successful DoS can halt production, delay shipments, and cascade to downstream suppliers, creating a tangible supply‑chain disruption risk for any organization that relies on Mitsubishi‑based automation.
Recommended Actions — 1️⃣ Verify firmware versions on all MELSEC iQ‑F devices; 2️⃣ Apply Mitsubishi‑issued firmware updates or mitigations immediately; 3️⃣ Segment control‑network traffic and restrict inbound UDP to trusted sources; 4️⃣ Deploy IDS/IPS signatures that detect abnormal UDP flood patterns; 5️⃣ Maintain an inventory of affected assets for rapid response. Source: CISA Advisory – ICSA‑26‑62‑01