No exploitation reported

CVE-2021-27663

No exploitation reported by the sources we read.

Published2021-08-30
WeaknessCWE-285

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2021-08-3018:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27663?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27663?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Johnsoncontrols ac2000 firmwareversion to verify

Branch	Affected	Fixed in	Source
10.x	≥ 10.1, ≤ 10.5	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-21-238-01 CISA1 known affected
Johnson Controls Controlled Electronic Management Systems CEM Systems AC2000
CEM Systems AC2000: Versions 10.1 through 10.5

Full record on NVD

Fix

Mitigation from the vendor CISA ICSA-21-238-01 · 1 productTo access the patch, affected users should contact a CEM support team.
Mitigation from the vendor CISA ICSA-21-238-01 · 1 productFor more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2021-15 v1

Advisories and patches

www.johnsoncontrols.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.18.2read 2026-10-23
NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.09.3read 2026-10-23
CNAweakness (CWE)CWE-285read 2026-10-23
FIRST EPSSEPSS score1.7 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-08-30
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-27663?

Is CVE-2021-27663 actively exploited?

Active exploitation of CVE-2021-27663 has not been confirmed. Its EPSS score was 1.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-27663?

CVE-2021-27663 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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