CVE-2025-61736

Communication outage via expired default certificate

Published Dec 17, 2025 · Updated Dec 17, 2025

Improper certificate-expiration validation in Johnson Controls iSTAR allows remote attackers to interrupt controller-server communications. Panels using the default TLS 1.2 certificate do not re-establish their encrypted C•CURE server connection after that certificate expires and communications are interrupted. Exploitation requires local-network access, the default certificate, its expiration, and a connection interruption; affected panels then remain disconnected.

CVSS severity7.1
High
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate-expiration validation in Johnson Controls iSTAR allows remote attackers to interrupt controller-server communications. Panels using the default TLS 1.2 certificate do not re-establish their encrypted C•CURE server connection after that certificate expires and communications are interrupted. Exploitation requires local-network access, the default certificate, its expiration, and a connection interruption; affected panels then remain disconnected.

The record

CVE
CVE-2025-61736
Published
Dec 17, 2025
Updated
Dec 17, 2025
Vendor
Johnson Controls
Product
iSTAR
Classifications
CWE-298, CAPEC-94, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 17, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=iSTAR All versions prior to TLS 1.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Johnson Controls · iSTARversion=iSTAR All versions prior to TLS 1.2

Published CVSS scores

7.1Johnson ControlsCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-298Improper Validation of Certificate Expiration
CAPEC-94Adversary in the Middle (AiTM)
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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