CVE-2023-4699: Mitsubishi Electric MELSEC-F Series FX3U-16MT/ES · Missing Authentication
Affects Mitsubishi Electric MELSEC-F Series FX3U-16MT/ESSource CVE Database V5
Not known to be exploited · CVSS 10.0 Critical.
Data as of 26 Oct 2026, 07:57 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mitsubishi Electric Corporation MELSEC-F Series FX3U-16MT/ES | Affected
| Fixed in– |
AI-suggested
1. Immediately implement strict network segmentation to isolate affected Mitsubishi Electric devices from general IT networks and limit access to trusted control networks only. 2. Deploy robust firewall rules and intrusion detection/prevention systems (IDS/IPS) to monitor and block unauthorized packets targeting these devices. 3. Restrict remote access to these control systems using VPNs with multi-factor authentication and limit access to essential personnel only. 4. Regularly audit and monitor network traffic for anomalous patterns indicative of exploitation attempts, such as unexpected command packets or resets. 5. Engage with Mitsubishi Electric support channels to obtain any available patches or firmware updates as soon as they are released. 6. Where patching is not immediately possible, consider deploying compensating controls such as application-layer gateways or protocol-aware proxies that enforce authentication. 7. Conduct thorough risk assessments and update incident response plans to include scenarios involving industrial control system compromise. 8. Train operational technology (OT) staff on the nature of this vulnerability and best practices for securing industrial networks. 9. Maintain an inventory of all affected devices and prioritize remediation based on criticality and exposure. 10. Collaborate with industry information sharing groups to stay informed about emerging threats and mitigation strategies.
Description
CVE-2023-4699 is a critical vulnerability affecting multiple Mitsubishi Electric MELSEC series CPU modules and CNC systems. It involves missing authentication for critical functions, allowing remote unauthenticated attackers to send specially crafted packets to execute arbitrary commands. This can lead to unauthorized disclosure or tampering of control programs and potentially cause denial-of-service by resetting devices to factory settings. The vulnerability affects all versions of the listed products and has a CVSS score of 10. Exploitation requires no authentication or user interaction and can impact confidentiality, integrity, and availability. No known exploits are currently reported in the wild. European industrial environments using these Mitsubishi Electric products are at significant risk, especially in manufacturing and critical infrastructure sectors. Immediate mitigation involves network segmentation, strict access controls, and monitoring for anomalous traffic targeting these devices.