CVE-2026-8805: Mitsubishi Electric MELSEC iQ-F FX5-EIP DoS (pending)
noindex and left out of the sitemap until more data is confirmed.CVE-2026-8805 is an integer overflow in the EtherNet/IP function of Mitsubishi Electric's MELSEC iQ-F FX5-EIP module that lets a remote attacker cause a denial-of-service condition by rapidly opening many TCP connections to it; NVD has deferred its own analysis, so this page stays noindex and presents only the vendor-submitted score until NVD publishes its own.
Vulnerability summary
| Vulnerability ID | CVE-2026-8805 |
|---|---|
| CVSS score | Not yet scored by NVD |
| EPSS score | 0.00637 |
| CISA KEV | No |
| Source | NVD |
| Published | 2026-06-19T03:16:14.850 |
Affected components
| Component | CPE | Version range |
|---|---|---|
| Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP Module | — | FX5-EIP versions 1.000 and prior (fixed in version 1.001 or later) |
What this means
CVE-2026-8805 is an integer overflow or wraparound vulnerability (CWE-190) in the EtherNet/IP function of the Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP module. NVD's description, drawn from Mitsubishi Electric's own CVE submission, states the flaw "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" (NVD).
NVD tracks the CVE with status "Deferred": the only severity data on record is Mitsubishi Electric's own CVSS v4.0 submission of 8.7 (high), 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, with no NVD-published independent score, so this page leaves cvss_score unset rather than presenting that figure as NVD-confirmed (NVD).
CISA's ICS advisory ICSA-26-169-05, republishing Mitsubishi Electric's own advisory 2026-002, confirms the same CVSS v3.1 score of 7.5 (high), vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, lists FX5-EIP versions 1.000 and prior as affected, states the fix is version 1.001 or later, and recommends standard network-segmentation mitigations (firewalls/VPNs, confining the product to a LAN, enabling its IP filter function) while reporting no known public exploitation (CISA ICS Advisory ICSA-26-169-05).
This CVE is not listed in the CISA Known Exploited Vulnerabilities catalog as of 2026-10-26, and FIRST scores the probability of exploitation at 0.00637 (50.266th percentile) (CISA KEV, FIRST EPSS).
Because NVD has not finished its own severity analysis, this page does not yet meet the minimum data bar for indexing and will be revisited once that analysis is published. In the meantime, operators of MELSEC iQ-F FX5-EIP modules should upgrade to firmware 1.001 or later and keep the module off any network reachable from untrusted hosts, since the denial-of-service path only requires the ability to open TCP connections to it.
Evidence
- Integer overflow in the EtherNet/IP function lets a remote attacker cause denial-of-service by rapidly establishing a large number of TCP connections (CWE-190). — NVD
- NVD status is "Deferred" with Mitsubishi Electric-submitted CVSS v4.0 8.7; no NVD-published independent score as of 2026-10-26. — NVD
- CVSS v3.1 7.5 (high); affects FX5-EIP versions 1.000 and prior, fixed in 1.001 or later; standard network-segmentation mitigations recommended; no known public exploitation. — CISA ICS Advisory ICSA-26-169-05
- Not present in the CISA KEV catalog as of 2026-10-26. — CISA KEV
- EPSS score is 0.00637 (50.266th percentile) as of 2026-10-26. — FIRST EPSS