Security readout for executives and security teams
Plain-English summary
This issue affects Honeywell Experion PKS C200, C200E, C300, and ACE controllers. A remote, unauthenticated attacker could execute arbitrary code or cause a denial of service. For operational technology environments, the main business risk is loss of controller integrity or availability in systems that may support production, safety, or process operations.
Executive priority
Treat this as a critical OT risk if the affected Honeywell controllers are deployed. The urgency depends on exposure and process criticality, but unauthenticated remote code execution and denial of service against controllers justify prompt inventory, vendor-guided remediation, and access restriction.
Technical view
CVE-2021-38395 is a CWE-74 output neutralization flaw in specified Honeywell Experion PKS controllers. The CVSS 3.1 score is 9.1 with network attack vector, low complexity, no privileges, and no user interaction. The published impact indicates high integrity and availability impact, with no confidentiality impact stated.
Likely exposure
Exposure is likely limited to organizations operating Honeywell Experion PKS C200, C200E, C300, or ACE controllers. Risk is highest where controller management or operational interfaces are reachable from broad plant networks, corporate networks, remote access paths, or untrusted segments.
Exploitation context
The source bundle does not identify active exploitation, and the CVE is not marked as CISA KEV. However, the CVSS vector indicates remote, unauthenticated exploitation with low complexity, so vulnerable exposed controllers should be treated as urgent operational risk.
Researcher notes
Evidence is limited to the CVE metadata, CISA advisory reference, and Honeywell notification reference. Do not assume broader Honeywell product impact, active exploitation, or a specific patch level unless confirmed in the vendor advisory. Focus validation on model presence, version applicability, and reachable attack surface.
Mitigation direction
- Identify all Experion PKS C200, C200E, C300, and ACE controller deployments.
- Review Honeywell notification SN2021-02-22-01 for vendor-specific corrective guidance.
- Review CISA ICSA-21-278-04 for operational mitigation guidance.
- Restrict controller access to trusted OT management paths only.
- Prioritize remediation for systems supporting critical production or safety processes.
Validation and detection
- Confirm whether any affected controller models are present in asset inventory.
- Verify installed controller versions against Honeywell’s advisory criteria.
- Check network paths that can reach affected controller interfaces.
- Validate that remediation follows Honeywell and CISA guidance.
- Document any compensating controls where vendor remediation is delayed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-74: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-38395 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H3.95.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Source materials
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.