C200 FirmwareOperating system · Honeywell

CVE-2021-38397

CRITICAL · 10.0 CVSS v3.1 Published 2022-10-28
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
Honeywell Experion PKS C200, C200E, C300, and ACE controllers are vulnerable to unrestricted file uploads, which may allow an attacker to remotely execute arbitrary code and cause a denial-of-service condition.

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 · moderate confidence

Honeywell Experion PKS controllers (C200, C200E, C300, ACE) contain an unrestricted file upload vulnerability that allows attackers to upload arbitrary files to the system, enabling remote code execution and potential denial-of-service conditions.

MitigationApply vendor-provided patches for Experion PKS controllers immediately and implement network segmentation to restrict unauthorized access to ICS equipment.

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
C200 FirmwareOperating system
Affected:all versions
C200e FirmwareOperating system
Affected:all versions
C300 FirmwareOperating system
Affected:all versions
Application Control Environment FirmwareOperating system
Affected:all versions

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 Experion PKS controllers in the environment
    Review ICS asset inventory, network scans, or device logs to locate Honeywell C200, C200E, C300, or ACE controllers. Check device hostnames, banners, or MAC vendor prefixes for Honeywell identifiers.
    Affected if Any Honeywell Experion PKS controller (C200, C200E, C300, or ACE) is present in the network inventory.
  2. Confirm controller firmware version
    Access the controller via its management interface or consult the Experion system database to retrieve the installed firmware version for each identified controller.
    Affected if The controller firmware version matches C200, C200E, C300, or ACE (all versions of these models are affected per vendor scope).
  3. Check if file upload functionality is enabled
    Review the controller configuration or Experion system settings to determine if the file upload/upload feature is enabled. This may be accessible via the controller web interface or associated management software.
    Affected if The file upload feature is enabled and accessible on the controller.
  4. Assess network accessibility of the controller
    Perform network reachability tests from untrusted network segments to the controller management ports. Review firewall rules and access control lists protecting the controller.
    Affected if The controller management interface or file upload functionality is reachable from a network segment that is not fully trusted or is exposed to less privileged users.

You are affected if your environment contains any Honeywell Experion PKS C200, C200E, C300, or ACE controller with the file upload feature accessible from a network path that could be exploited by an attacker.

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-provided patches for Experion PKS controllers immediately and implement network segmentation to restrict unauthorized access to ICS equipment.

Fix this in C200 Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation20.0 h
  • Testing16.0 h
  • Review / QA12.0 h
60.0 hours of engineering $10,560
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $16,896.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-38397 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2021-38397 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