CVE-2025-53696: Johnson Controls iSTAR Ultra · Download of Code Without Integrity Check
Affects Johnson Controls iSTAR UltraSource CVE Database V5
Not known to be exploited · CVSS 9.3 Critical.
Data as of 26 Oct 2026, 06:26 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| Johnson Controls, Inc iSTAR Ultra | Affected
| 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.