CVE-2026-3611
Honeywell IQ4x BMS Controller Missing authentication for critical function
- Published
- Updated
- Reserved
- Assigned by
- icscert
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| icscertCNA (assigner) | 4.0 | Critical10.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| icscertCNA (assigner) | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Analyzed | 4.0 | Critical10.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 5.7% · top 6.9% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 10.0.
Weakness
Affected products
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
- affected v3.50_3.44 – ≤ 4.36 (build 4.3.7.9)
What to do
Workaround: Honeywell is aware of the issue, but has not released a fix. For more information, contact Honeywell directly. [https://www.honeywell.com/us/en/contact](https://www.honeywell.com/us/en/contact).
References (3)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-3611)Record last updated .