dbcve.org
G 50a FirmwareOperating system · Mitsubishi

CVE-2021-20595

HIGH · 8.2 CVSS v3.1 Published 2021-07-13
Fix available
A fix is available. Upgrade to after 7.09 or later.
See remediation →
91/100
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
Improper Restriction of XML External Entity Reference vulnerability in Mitsubishi Electric Air Conditioning System/Centralized Controllers (G-50A Ver.3.35 and prior, GB-50A Ver.3.35 and prior, GB-24A Ver.9.11 and prior, AG-150A-A Ver.3.20 and prior, AG-150A-J Ver.3.20 and prior, GB-50ADA-A Ver.3.20 and prior, GB-50ADA-J Ver.3.20 and prior, EB-50GU-A Ver 7.09 and prior, EB-50GU-J Ver 7.09 and prior, AE-200A Ver 7.93 and prior, AE-200E Ver 7.93 and prior, AE-50A Ver 7.93 and prior, AE-50E Ver 7.93 and prior, EW-50A Ver 7.93 and prior, EW-50E Ver 7.93 and prior, TE-200A Ver 7.93 and prior, TE-50A Ver 7.93 and prior, TW-50A Ver 7.93 and prior, CMS-RMD-J Ver.1.30 and prior), Air Conditioning System/Expansion Controllers (PAC-YG50ECA Ver.2.20 and prior) and Air Conditioning System/BM adapter(BAC-HD150 Ver.2.21 and prior) allows a remote unauthenticated attacker to disclose some of data in the air conditioning system or cause a DoS condition by sending specially crafted packets.

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

This is an XML External Entity (XXE) vulnerability in Mitsubishi Electric air conditioning controllers. The affected devices parse XML without properly restricting external entity references, allowing remote unauthenticated attackers to send specially crafted XML packets that can disclose system data or cause denial of service.

MitigationApply vendor firmware updates to all affected controller models. If patches are unavailable, disable XML processing or restrict network access to these devices.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
G 50a FirmwareOperating system
Affected:>= 2.50, <= 3.35
Gb 50a FirmwareOperating system
Affected:>= 2.50, <= 3.35
Ag 150a A FirmwareOperating system
Affected:<= 3.20
Ag 150a J FirmwareOperating system
Affected:<= 3.20
Gb 50ada A FirmwareOperating system
Affected:<= 3.20
Gb 50ada J FirmwareOperating system
Affected:<= 3.20
Eb 50gu A FirmwareOperating system
Affected:<= 7.09
Eb 50gu J FirmwareOperating system
Affected:<= 7.09

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
Low
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 the controller model
    Access the device web interface or check network inventory to determine the exact model (G 50a, Gb 50a, Ag 150a A, Ag 150a J, Gb 50ada A, Gb 50ada J, Eb 50gu A, or Eb 50gu J)
    Affected if The model is not one of the eight affected models listed in the CVE
  2. Check the firmware version
    Log into the controller web interface or use the device's management protocol to retrieve the current firmware version
    Affected if The firmware version falls within any of these ranges: G 50a or Gb 50a with version 2.50-3.35; Ag 150a A/J or Gb 50ada A/J with version 3.20 or below; Eb 50gu A/J with version 7.09 or below
  3. Verify XML management interface is accessible
    Attempt to access the device XML endpoint (typically port 80/443 or a known XML-based API endpoint) to confirm the XML parsing feature is enabled
    Affected if The XML management interface is exposed and accepts XML input without restrictions

You are affected if you have any of the eight Mitsubishi controller models (G 50a, Gb 50a, Ag 150a A/J, Gb 50ada A/J, or Eb 50gu A/J) running the specified firmware versions, and the XML management interface is accessible on the network.

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
Upgrade available Upgrade to a release after 7.09
Interim mitigation

Apply vendor firmware updates to all affected controller models. If patches are unavailable, disable XML processing or restrict network access to these devices.

Fix this in G 50a Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing12.0 h
  • Review / QA4.0 h
48.0 hours of engineering $8,440
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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-2021-20595 in production — separate from our analysis above.

No notes yet

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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