CVE-2026-3611

CRITICAL

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 b...

Affects 0 products across 2 vendors.

BCS7.45
CVSS 3.110.0
CVSS v410.0
EPSS5.6%
Percentile92th
PatchPatched
CVSS Vector — Plain English Remotely exploitable over the network, low complexity, no authentication required, no user interaction needed, can impact systems beyond the vulnerable component, full confidentiality impact, full integrity impact, full availability impact.
CWE Weakness Definitions
CWE-306: Missing Authentication for Critical Function

Software does not perform any authentication for functionality that requires a verified identity.

Related Attack Patterns (CAPEC)
CAPEC-12 Choosing Message Identifier
via CWE-306
CAPEC-36 Using Unpublished Interfaces or Functionality
via CWE-306
CAPEC-62 Cross Site Request Forgery
via CWE-306
CAPEC-166 Force the System to Reset Values
via CWE-306
CAPEC-216 Communication Channel Manipulation
via CWE-306

Mapping is CWE-to-CAPEC per MITRE CAPEC 3.9.

◆ SAGE Intelligence — CITED Relevance Research Team

The Honeywell IQ4x building management controller exposes its full web-based HMI without authentication in its factory-default configuration, allowing unauthenticated access with full read/write privileges. This can lead to unauthorized control and potential denial of service for legitimate operators.

BSID: BS-2026-GLOBAL-152032-C • Model: Qwen/Qwen2.5-72B-Instruct-AWQ • Confidence: HIGH

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Frequently Asked Questions
What is CVE-2026-3611?
The Honeywell IQ4x building management controller exposes its full web-based HMI without authentication in its factory-default configuration, allowing unauthenticated access with full read/write privileges. This can lead to unauthorized control and potential denial of service for legitimate operators.
What is the CVSS score for CVE-2026-3611?
CVE-2026-3611 has CVSS 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. EPSS: 5.6%.
Is CVE-2026-3611 actively exploited?
No confirmed active exploitation of CVE-2026-3611 as of 2026-05-30.
How do I remediate CVE-2026-3611?
Priority: IMMEDIATE. Advisory: https://www.cisa.gov/news-events/ics-advisories/icsa-26-069-03
What systems are affected by CVE-2026-3611?
CVE-2026-3611 affects: Full, Honeywell.
What NERC-CIP standard applies to CVE-2026-3611?
NERC CIP CIP-007 CIP-007-R2: This CVE violates CIP-007-R2 because it allows unauthorized access to the control system, which could compromise the security of the electronic security perimeter.
What IEC 62443 requirement maps to CVE-2026-3611?
IEC 62443 SR 7.6: This CVE maps to SR 7.6 because it involves the lack of proper authentication mechanisms, which is essential for protecting against unauthorized access to the control system.
Vulnerability Details
CVE IDCVE-2026-3611
BSIDBS-2026-GLOBAL-152032-C BreachSpider Global ID
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published2026-03-12
Last Modified2026-03-13
ICS Relevance80%
Weakness (CWE)
Verticals
ICS-OT
SourceNVD
Official 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.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

The vulnerability exists due to the lack of authentication controls in the factory-default configuration of the Honeywell IQ4x building management controller. An attacker can access the web-based HMI and create a new account with administrative privileges, effectively locking out legitimate operators.

Exploitation Likelihood: MEDIUM

Affected Products
VendorProductFixed Version
Full —
Honeywell —
Remediation
View Vendor Advisory →

Remediation Priority: IMMEDIATE

Threat Intelligence
● Threat Intelligence Validated: August 2026 | Threat Age: 143 Days
CISA KEVNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
● Virtual Patch — CITED Relevance SAGE Engine MEDIUM CONFIDENCE

Implement network segmentation to isolate the Honeywell IQ4x controller from untrusted networks and apply strict access controls to limit who can reach the HTTP interface.

SURICATA RULE
alert http any any -> any any (msg:"Honeywell IQ4x HMI Unauthenticated Access Attempt"; flow:established,to_server; content:"/U.htm"; http_uri; sid:9100643; rev:1;)
NERC CIP: CIP-007 CIP-007-R2
This CVE violates CIP-007-R2 because it allows unauthorized access to the control system, which could compromise the security of the electronic security perimeter.
IEC 62443: SR 7.6
This CVE maps to SR 7.6 because it involves the lack of proper authentication mechanisms, which is essential for protecting against unauthorized access to the control system.

Virtual patch generated by CITED Relevance SAGE. Validate in isolated environment before production deployment. Compensating control only - does not replace vendor patch.

SAGE Enrichment Record — provenance & audit hash
ModelQwen/Qwen2.5-72B-Instruct-AWQ
ConfidenceHIGH
Enriched At2026-05-24
SHA-512 Audit Hash14691bee585268ff391abfe0b1278d1132129c7f34fce7db05b752b7a8779873b982aed058a8a57e9cbf15fa35c505448f3b2f68d3dbf226624f33f1a9e63602
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