How severe is CVE-2021-38395?

CVE-2021-38395 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-38395 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38395?

CVE-2021-38395 primarily affects Honeywell C200 Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-38395?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-38395 published?

CVE-2021-38395 was published on 2022-10-28 and last updated on 2026-06-17.

CVE-2021-38395

CVE-2021-38395 is a critical-severity vulnerability in Honeywell C200 Firmware with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Honeywell C200 Firmware
Published: 2022-10-28
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-38395?: 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.
How severe is CVE-2021-38395?: CVE-2021-38395 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-38395 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38395?: CVE-2021-38395 primarily affects Honeywell C200 Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-38395?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-38395 published?: CVE-2021-38395 was published on 2022-10-28 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:honeywell:c200_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:honeywell:c200e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:honeywell:c300_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:honeywell:application_control_environment_firmware:-:*:*:*:*:*:*:*

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