# CVE-2026-8805: Mitsubishi Electric MELSEC iQ-F FX5-EIP integer overflow in EtherNet/IP

Source: https://junglewise.ai/threats/cve-2026-8805-mitsubishi-electric-melsec-iq-f-fx5-eip-integer-overflow-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-19. Updated: 2026-06-21  
License: CC BY 4.0 with a link back

CVE-2026-8805 · Severity: info · CVSS 8.7 · Published 2026-06-19

A vulnerability exists in the Mitsubishi Electric MELSEC iQ-F Series FX5-EIP module, which is used in industrial automation to manage EtherNet/IP communications. An attacker can crash the module by rapidly opening many network connections, leading to a denial-of-service condition. This can disrupt manufacturing processes, stop industrial operations, and require manual intervention to restore service.

Vendors: [Mitsubishi Electric](https://junglewise.ai/threats/vendors/mitsubishi-electric).

## Quick answers

**Is CVE-2026-8805 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8805 being exploited in the wild.

**How severe is CVE-2026-8805?** Informational severity, with a CVSS score of 8.7, published 19 June 2026.

**Which products and versions are affected?** Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP Module 1.000 and prior.

**Is there a fix for CVE-2026-8805?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-8805 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-8805?** Check whether you run Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP Module at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer overflow or wraparound vulnerability (CWE-190) exists in the EtherNet/IP function of the FX5-EIP module. The flaw is triggered when the device attempts to manage a rapid influx of TCP connections, leading to an inconsistency in the internal connection management process and subsequent improper memory access. A remote, unauthenticated attacker can exploit this over the network to cause a denial-of-service (DoS) condition. Mitsubishi Electric has released firmware version 1.001 to address this issue.

## Affected products

- Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP Module FX5-EIP 1.000 and prior

## Timeline

- 2026-06-18: advisory: CISA and Mitsubishi Electric published advisories
- 2026-06-19: disclosed: JVN publication date

## References

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