CVE-2021-27662

8.6 HIGH 0.8% exploit odds Fix listed

What it is

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

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data tampering.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-09-15 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:45 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 8.6 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-09-15 13:15 UTC
Last modified: 2026-06-17 03:45 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-294
Record status: Modified

Affected

Johnsoncontrols Kantech kt-1 Door Controller Firmware ≤ 3.01

Attack profile CVSS 3.1 · 8.6

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: High
Availability: Low

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-27662.md and follow it. Check whether this project is affected by CVE-2021-27662. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record