CVE-2021-27663

Name: CVE-2021-27663
Creator: NVD / NIST
Published: 2021-08-30T18:15:08.663+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.67%

Last modified Jun 17, 2026

CVE-2021-27663 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A vulnerability in versions 10.1 through 10.5 of Johnson Controls CEM Systems AC2000 allows a remote attacker to access to the system without adequate authorization. This issue affects: Johnson Controls CEM Systems AC2000 10.1; 10.2; 10.3; 10.4; 10.5.. EPSS estimates a 1.67% chance of exploitation in the next 30 days.

Description

A vulnerability in versions 10.1 through 10.5 of Johnson Controls CEM Systems AC2000 allows a remote attacker to access to the system without adequate authorization. This issue affects: Johnson Controls CEM Systems AC2000 10.1; 10.2; 10.3; 10.4; 10.5.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.67%

73.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-285

Affected Software

Vendor	Product	Versions
Johnsoncontrols	Ac2000 Firmware	>= 10.1, <= 10.5

References

https://us-cert.gov/ics/advisories/ICSA-21-238-01Third Party Advisory, US Government Resource
https://www.johnsoncontrols.com/cyber-solutions/security-advisoriesVendor Advisory
https://us-cert.gov/ics/advisories/ICSA-21-238-01Third Party Advisory, US Government Resource
https://www.johnsoncontrols.com/cyber-solutions/security-advisoriesVendor Advisory

Timeline

Published: Aug 30, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27663?

How severe is CVE-2021-27663?

CVE-2021-27663 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.67% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27663?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-27663?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST