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CVE-2025-53696VulnerabilityPublished Updated

CVE-2025-53696: Johnson Controls iSTAR Ultra · Download of Code Without Integrity Check

Affects Johnson Controls iSTAR UltraSource CVE Database V5

0

Not known to be exploited · CVSS 9.3 Critical.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Affected software

ProductAffectedFixed in
Johnson Controls, Inc iSTAR UltraAffected
  • =0
Fixed in–

AI-suggested

To mitigate the risks posed by CVE-2025-53696, European organizations should implement a multi-layered approach: 1) Immediately verify the firmware version of all iSTAR Ultra devices and consult Johnson Controls for any available patches or firmware updates addressing this vulnerability. 2) If patches are not yet available, restrict local access to devices to trusted personnel only, and enhance monitoring of privileged user activities to detect any anomalous behavior. 3) Employ network segmentation to isolate access control systems from general IT networks, limiting the attack surface and preventing lateral movement. 4) Implement strict physical security controls to prevent unauthorized local access to devices. 5) Use cryptographic verification tools where possible to manually validate firmware integrity before deployment. 6) Establish incident response plans specifically addressing potential firmware compromise scenarios, including forensic analysis and device replacement procedures. 7) Engage with Johnson Controls support channels for advisories and participate in information sharing with industry peers and national cybersecurity centers to stay informed about emerging exploit techniques or patches. These steps go beyond generic advice by focusing on controlling local access, enhancing monitoring, and preparing for incident response specific to firmware integrity compromise.

Description

iSTAR Ultra performs a firmware verification on boot, however the verification does not inspect certain portions of the firmware. These firmware parts may contain malicious code. Tested up to firmware 6.9.2, later firmwares are also possibly affected.

References

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