PT-2026-24600 · Honeywell · Iq3+6

Gjoko Krstic

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Published

2026-03-11

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Updated

2026-04-15

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CVE-2026-3611

CVSS v3.1

10

Critical

VectorAV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Name of the Vulnerable Software and Affected Versions Honeywell IQ4x building management controller (affected versions not specified)
Description The Honeywell IQ4x building management controller exposes its full web-based Human Machine Interface (HMI) without authentication in its factory-default configuration. When no user module is configured, security is disabled by design, and the system operates under a System Guest context, granting read/write privileges to anyone who can access the HTTP interface. Authentication is only enforced after a web user is created through the U.htm function, which dynamically enables the user module. Because this function is accessible before 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 prevent legitimate operators from accessing local and web-based configuration and administration.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Missing Authentication

Weakness Enumeration

CWE-306

Related Identifiers

CVE-2026-3611

Affected Products

Iq3
Iq412
Iq41X
Iq422
Iq4E
Iq4Nc
Iqeco