Vulnerability · CVE-2026-3611
The Honeywell IQ4x building management controller, exposes its full web-based HMI without authentication in its factory-default configuration.
Published Mar 12, 2026 · corrected/updated Jun 17, 2026 · honeywell iq4e firmware · evidence confidence medium
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.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-3611 is a critical public vulnerability record for honeywell iq4e firmware. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether honeywell iq4e firmware is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: honeywell/iq412 firmware; honeywell/iq41x firmware; honeywell/iq422 firmware; honeywell/iq4e firmware. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 10.0 (technical impact); EPSS awaiting sync or unavailable (not low probability). It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-306. Sources contributing to this record: cve_org, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 12, 2026 · NIST NVD
Detected
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
Jun 17, 2026 · NIST NVD
Updated
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
Affected
- cpe honeywell/iq412 firmwareversion unspecified
- cpe honeywell/iq41x firmwareversion unspecified
- cpe honeywell/iq422 firmwareversion unspecified
- cpe honeywell/iq4e firmwareversion unspecified
- cpe honeywell/iq4nc firmwareversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-3611
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-2026-3611
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
nvd.nist.gov