How severe is CVE-2021-27662?

CVE-2021-27662 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability low.

Is CVE-2021-27662 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27662?

CVE-2021-27662 affects Johnsoncontrols Kantech Kt-1 Door Controller Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27662?

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

When was CVE-2021-27662 published?

CVE-2021-27662 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-27662

CVE-2021-27662 is a high-severity vulnerability in Johnsoncontrols Kantech Kt-1 Door Controller Firmware with a CVSS 3.x base score of 8.6. 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-294.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v2: 6.8
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-294
Affected product: Johnsoncontrols Kantech Kt-1 Door Controller Firmware
Published: 2021-09-15
Last modified: 2026-06-17

Description

The KT-1 door controller is susceptible to replay or man-in-the-middle attacks where an attacker can record and replay TCP packets. This issue affects Johnson Controls KT-1 all versions up to and including 3.01

Frequently asked questions

What is CVE-2021-27662?: The KT-1 door controller is susceptible to replay or man-in-the-middle attacks where an attacker can record and replay TCP packets. This issue affects Johnson Controls KT-1 all versions up to and including 3.01
How severe is CVE-2021-27662?: CVE-2021-27662 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability low.
Is CVE-2021-27662 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27662?: CVE-2021-27662 affects Johnsoncontrols Kantech Kt-1 Door Controller Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27662?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27662 published?: CVE-2021-27662 was published on 2021-09-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:johnsoncontrols:kantech_kt-1_door_controller_firmware:*:*:*:*:*:*:*:*

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