CVE-2026-21661

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.10% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 1.3% of scored records. A rank, not a probability.

NVD base score

8.4 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-10-26.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-05-06 16:21Z5 MO AGO

Last updated

2026-08-24 17:59Z2 MO AGO

Reserved

2026-01-02

Assigning CNA

jci

Record state

PUBLISHED

Severity

High (CVSS 8.4)

CNA CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

Weaknesses

• CWE-427Uncontrolled Search Path ElementBase

Data version

5.2

Document digest

db3a2c5e8ad120084c26ad18349f1ce98504dbdacb9aabee863c0e0030e8aba9

• www.johnsoncontrols.comhttps://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisories