CVE-2026-3611
The Honeywell IQ4x building management controller, exposes its full web-based HMI without authentication in its factory-default configuration.
Impact
The Honeywell IQ4x building management controller, exposes its full web-based HMI without authentication in its factory-default configuration. With no user module configured, security is disabled by design and the system operates under a System Guest (level 100) context, granting read/write privileges to any party able to reach the HTTP interface. Authentication controls are only enforced after a web user is created via U.htm, which dynamically enables the user module. Because this function is accessible prior to authentication, a remote user can create a new account with administrative read/write permissions enabling the user module and imposing authentication under attacker-controlled credentials. This action can effectively lock legitimate operators out of local and web-based configuration and administration.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Honeywell | Iq4e Firmware | before 3.30 |
| Honeywell | Iq412 Firmware | before 3.30 |
| Honeywell | Iq422 Firmware | before 3.30 |
| Honeywell | Iq4nc Firmware | before 3.30 |
| Honeywell | Iq41x Firmware | before 3.30 |