---
cve: "CVE-2026-3611"
severity: "CRITICAL"
cvss: 10.0
epss: "5.5%"
vendor: "Honeywell"
kev: false
exploited: false
published: "2026-03-12 21:16:27"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T08:19:20+02:00"
---

# CVE-2026-3611

> 10.0 CRITICAL · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Referenzen

- <https://www.cisa.gov/news-events/ics-advisories/icsa-26-069-03>
- <https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-069-03.json>
- <https://www.honeywell.com/us/en/contact>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-3611) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_