CVE-2021-38395

CRITICALNVD 9.19.8▲
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-10-28. NVD baseline CVSS 9.1; sources differ by 0.7.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Honeywell Experion PKS C200, C200E, C300, and ACE controllers are vulnerable to improper neutralization of special elements in output, which may allow an attacker to remotely execute arbitrary code and cause a denial-of-service condition.

CVSS v3
9.1
EG Score
9.8(medium)
EG Risk
59(Track)
EG Risk 59/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
55.1%
KEV
Not listed

Published

October 28, 2022

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Jul 22, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
generic

Process Automation | Honeywell

https://www.honeywellprocess.com/library/support/notifications/Customer/SN2021-02-22-01-Experion-C300-CCL.pdf
cisa Patch Available🔴 Active Exploitation

Honeywell Experion PKS and ACE Controllers | CISA

Honeywell Experion PKS and ACE Controllers | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/uscert/ics/advisories/icsa-21-278-04

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 101 total refreshes for this CVE.

  1. 2026-07-23 14:16 UTCEPSS rescore
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  75. 2026-05-25 13:04 UTCEG score recompute

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Frequently asked(5)

What is CVE-2021-38395?
CVE-2021-38395 is a critical vulnerability published on October 28, 2022. Honeywell Experion PKS C200, C200E, C300, and ACE controllers are vulnerable to improper neutralization of special elements in output, which may allow an attacker to remotely execute arbitrary code and cause a denial-of-service condition.
When was CVE-2021-38395 disclosed?
CVE-2021-38395 was first published in the National Vulnerability Database on October 28, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-38395 actively exploited?
CVE-2021-38395 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 55.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-38395?
CVE-2021-38395 has a CVSS v3 base score of 9.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.8.
How do I remediate CVE-2021-38395?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-38395, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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