Security readout for executives and security teams
Plain-English summary
This vulnerability affects Honeywell Experion PKS C200, C200E, C300, and ACE controllers. A network attacker may be able to traverse relative paths and read files or directories they should not access. The business risk is unauthorized disclosure from industrial control assets, not confirmed system takeover or disruption in the provided sources.
Executive priority
Treat this as a high-priority OT confidentiality issue. Prioritize asset identification and network exposure reduction, then confirm Honeywell-supported remediation. Escalation is warranted if affected controllers are reachable beyond tightly controlled industrial networks.
Technical view
CVE-2021-38399 is a CWE-23 relative path traversal issue in listed Honeywell Experion PKS controllers. The CVSS 3.1 score is 7.5: network reachable, low complexity, no privileges, no user interaction, with high confidentiality impact and no stated integrity or availability impact.
Likely exposure
Exposure is most relevant where affected Honeywell controllers are reachable over networks accessible to untrusted users or poorly segmented enterprise paths. The bundle does not identify specific vulnerable firmware versions, exposed services, or internet prevalence.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Risk is still material because the CVSS vector indicates unauthenticated network access with low attack complexity and high confidentiality impact.
Researcher notes
Evidence supports path traversal and high confidentiality impact only. The bundle does not provide exploit details, specific vulnerable firmware builds, patch versions, or active exploitation evidence. Validation should focus on affected-model presence, reachability, and vendor advisory mapping.
Mitigation direction
- Review Honeywell SN2021-02-22-01 and CISA ICSA-21-278-04 for official remediation guidance.
- Inventory Experion PKS C200, C200E, C300, and ACE controllers.
- Limit controller network access to trusted engineering and operations systems.
- Validate segmentation between enterprise networks and affected controller environments.
- Avoid inventing patches; confirm supported updates or compensating controls with Honeywell.
Validation and detection
- Compare asset inventory against the affected controller list in the CVE source bundle.
- Confirm whether affected controllers are reachable from non-operations networks.
- Check vendor advisory status for each deployed controller model.
- Review monitoring logs for unauthorized file or directory access indicators.
- Document unresolved firmware, exposure, and compensating-control gaps.
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-23: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-38399 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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:H/I:N/A:N3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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.
Relative Path Traversal
Relative Path Traversal represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.