CVE-2026-8805

Denial-of-service (DoS) vulnerability in MELSEC iQ-F Series EtherNet/IP module

Published Jun 19, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Description

Integer Overflow or Wraparound vulnerability in the EtherNet/IP function of Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP module FX5-EIP versions 1.000 and prior allows a remote attacker to cause a denial-of-service (DoS) condition in the affected product by rapidly establishing a large number of TCP connections to it, resulting in an inconsistency in the product's internal connection management process and triggering improper memory access.

Analysis

Technical impact

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.

Affected Systems

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.

Risk and Exploitability

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Mitsubishi Electric Corporation

Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP Module FX5-EIP

unaffected

Version	Status	Constraints
`versions 1.000 and prior`	affected	—

No data.

Vendor Product Versions

Mitsubishi Electric

Melsec Iq-f Series Fx5-enet/ip Ethernet Module Fx5-enet/ip

Version	Status	Scheme	Platform
`[0,1.000]`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the vendor’s firmware or software update that addresses the integer overflow issue.
Restrict network access to the module by limiting the number of concurrent TCP connections and enforcing strict firewall rules.
Disable unused EtherNet/IP services or segments to reduce the attack surface.
Implement monitoring for abnormal connection patterns and maintain network segmentation to isolate the device from critical control traffic.

Generated by OpenCVE AI on June 19, 2026 at 04:20 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.637% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://jvn.jp/vu/JVNVU97140216/
https://www.cisa.gov/news-events/ics-advisories/icsa-26-169-05
https://www.mitsubishielectric.com/psirt/vulnerability/pdf/2026-002_en.pdf

History

Jun 24, 2026 8:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Mitsubishi Electric Mitsubishi Electric melsec Iq-f Series Fx5-enet/ip Ethernet Module Fx5-enet/ip
Vendors & Products		Mitsubishi Electric Mitsubishi Electric melsec Iq-f Series Fx5-enet/ip Ethernet Module Fx5-enet/ip

Jun 22, 2026 3:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jun 19, 2026 3:00 AM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Integer Overflow or Wraparound vulnerability in the EtherNet/IP function of Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP module FX5-EIP versions 1.000 and prior allows a remote attacker to cause a denial-of-service (DoS) condition in the affected product by rapidly establishing a large number of TCP connections to it, resulting in an inconsistency in the product's internal connection management process and triggering improper memory access.
Title		Denial-of-service (DoS) vulnerability in MELSEC iQ-F Series EtherNet/IP module
Weaknesses		CWE-190
References		https://jvn.jp/vu/JVNVU97140216/ https://www.cisa.gov/news-events/ics-advisories/icsa-26-169-05 https://www.mitsubishielectric.com/psirt/vulnerability/pdf/2026-002_en.pdf
Metrics		cvssV4_0 `{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}`