What is CVE-2021-38399?

CVE-2021-38399 is a high-severity vulnerability in Honeywell Application Control Environment, classified under Relative Path Traversal. CVSS score: 7.5/10. Published 2022-10-28.

How severe is CVE-2021-38399?

High severity. CVSS v3 base score is 7.5 out of 10.

Path Traversal in Honeywell Application Control Environment

CVE-2021-38399

Honeywell Experion PKS C200, C200E, C300, and ACE controllers are vulnerable to relative path traversal, which may allow an attacker access to unauthorized files and directories.

Published 2022-10-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Weakness classification (CWE)

References

www.cisa.gov/uscert/ics/advisories/icsa-21-278-04 (US Government Resource, Third Party Advisory)
www.honeywellprocess.com/library/support/notifications/Customer/SN2021-02-22-01… (Product)

Frequently asked questions

What is CVE-2021-38399?: CVE-2021-38399 is a high-severity vulnerability in Honeywell Application Control Environment, classified under Relative Path Traversal. CVSS score: 7.5/10. Published 2022-10-28.
How severe is CVE-2021-38399?: High severity. CVSS v3 base score is 7.5 out of 10.