dbcve.org
Missing AuthenticationWeakness · CWE-306

CVE-2025-3699

CRITICAL · 9.8 CVSS v3.1 Published 2025-06-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
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
Missing Authentication for Critical Function vulnerability in Mitsubishi Electric Corporation G-50 all versions, G-50-W all versions, G-50A all versions, GB-50 all versions, GB-50A all versions, GB-24A all versions, G-150AD all versions, AG-150A-A all versions, AG-150A-J all versions, GB-50AD all versions, GB-50ADA-A all versions, GB-50ADA-J all versions, EB-50GU-A all versions, EB-50GU-J all versions, AE-200J all versions, AE-200A all versions, AE-200E all versions, AE-50J all versions, AE-50A all versions, AE-50E all versions, EW-50J all versions, EW-50A all versions, EW-50E all versions, TE-200A all versions, TE-50A all versions, TW-50A all versions, and CMS-RMD-J all versions allows a remote unauthenticated attacker to bypass authentication and then control the air conditioning systems illegally, or disclose information in them by exploiting this vulnerability. In addition, the attacker may tamper with firmware for them using the disclosed information.

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

Missing authentication in multiple Mitsubishi Electric building automation controllers (HVAC systems) allows remote unauthenticated attackers to bypass authentication entirely and gain full control of air conditioning systems, read sensitive information, and modify firmware. The CVSS 9.8 reflects trivial network-exploitable remote code execution equivalent with no privileges required.

MitigationApply vendor firmware patches when available; prior to patch deployment, isolate affected devices on restricted network segments and implement compensating controls such as firewall rules limiting access to authorized management stations.

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
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 Mitsubishi Electric HVAC controllers on the network
    Scan the network for devices with Mitsubishi Electric vendor-specific HTTP headers, or physically inspect building automation panels for model numbers such as City Multi, Mr. Slim, or other Mitsubishi HVAC controllers. Check network documentation or asset inventories for building management system (BMS) components.
    Affected if Any Mitsubishi Electric building automation controller is present on the network without documented firmware patching.
  2. Determine the controller firmware version
    Access the controller web interface (if enabled) and navigate to the system information or about page. For controllers without a web UI, use the vendor's configuration software (such as Mitsubishi Electric's MELD Cloud or local management tool) connected directly to the controller via USB or Ethernet to read the firmware version.
    Affected if The installed firmware version is unpatched and falls within the affected version range for this CVE (compare against vendor release notes for CVE-2025-3699 patches).
  3. Check if remote/network management interface is enabled
    Examine the controller network settings via its web UI or configuration software. Look for enabled protocols such as HTTP/HTTPS web server, MODBUS/TCP, BACnet/IP, or vendor-specific remote management ports that allow external network access.
    Affected if Remote network management or web-based access is enabled, exposing the authentication-bypass attack surface to the network.
  4. Verify authentication is actually enforced on accessible interfaces
    Attempt to access the controller web interface or API endpoints without providing credentials. Check if unauthenticated requests are rejected with a login prompt or if sensitive endpoints (configuration, firmware, device status) return data without authentication headers or session tokens.
    Affected if The controller allows unauthenticated access to administrative functions, configuration data, or firmware modification endpoints.

The environment is affected if it contains unpatched Mitsubishi Electric building automation controllers with remote network management enabled, and the authentication mechanism can be bypassed or is absent on accessible interfaces.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware patches when available; prior to patch deployment, isolate affected devices on restricted network segments and implement compensating controls such as firewall rules limiting access to authorized management stations.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,776.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-3699 — 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-2025-3699 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