dbcve.org
Integer OverflowWeakness · CWE-190

CVE-2026-8805

HIGH · 8.7 CVSS v4.0 Published 2026-06-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
96/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A remote integer overflow vulnerability exists in the EtherNet/IP function of Mitsubishi Electric FX5-EIP modules (v1.000 and prior). Attackers exploit this by rapidly establishing numerous TCP connections, causing inconsistency in the product's internal connection management process and triggering improper memory access, resulting in denial-of-service.

MitigationApply the vendor-provided firmware patch for FX5-EIP to address the integer overflow; implement network segmentation and connection rate limiting to reduce attack surface until patch deployment.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FX5-EIP module on the network
    Scan the network for devices with the FX5-EIP module or check Mitsubishi PLC configurations for installed add-on modules. Access the module through its web interface, GX Works3 engineering software, or SNMP if configured.
    Affected if An FX5-EIP module is present in the environment.
  2. Determine FX5-EIP firmware version
    Connect to the FX5-EIP module via GX Works3 or access its web interface and navigate to the module information or firmware version display. The version is typically shown in the module diagnostics or product information screen.
    Affected if The installed firmware version is 1.000 or any version prior to 1.000.
  3. Verify EtherNet/IP function is enabled
    Access the FX5-EIP module configuration through GX Works3 and check the EtherNet/IP settings. Look for the CIP connection settings or EIP configuration parameters where the EtherNet/IP function is activated.
    Affected if The EtherNet/IP function is enabled and configured for use.
  4. Assess network exposure of the module
    Review firewall rules, network segmentation, and access control lists to determine if the FX5-EIP module EtherNet/IP port (typically TCP 44818) is accessible from untrusted networks or the internet. Use network scanning to confirm open TCP ports on the device.
    Affected if The module is directly accessible from untrusted networks or the internet without adequate rate-limiting or network segmentation.

A user is affected if an FX5-EIP module with firmware version 1.000 or prior has the EtherNet/IP function enabled and is network-accessible to potential attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-provided firmware patch for FX5-EIP to address the integer overflow; implement network segmentation and connection rate limiting to reduce attack surface until patch deployment.

Recommended fix Moderate confidence

FX5-EIP firmware version greater than 1.000 (contact Mitsubishi Electric for exact fixed version)

  1. 1. Identify the current firmware version of the FX5-EIP EtherNet/IP module by accessing the module's configuration via GX Works3 or the module's web interface.
  2. 2. Contact Mitsubishi Electric technical support or visit the official Mitsubishi Electric download page to obtain the firmware update that addresses CVE-2026-8805.
  3. 3. Download the firmware update for the FX5-EIP module (version greater than 1.000).
  4. 4. Follow Mitsubishi Electric's official firmware update procedure, typically performed via the engineering workstation software GX Works3 or a dedicated firmware update tool.
  5. 5. Verify the firmware update was successful by confirming the new version number in the module's diagnostics.
  6. 6. Test that the EtherNet/IP functionality operates normally after the update.
Caveat Firmware updates on industrial control devices may require downtime and should be tested in a non-production environment first; verify compatibility with the MELSEC iQ-F Series CPU and other connected devices

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,192.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-8805 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8805 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data