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CVE-2026-3611

critical · 10

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.

10
CVSS
5.5%
EPSS (exploit prob.)
92nd
EPSS percentile
2026-03-12
Published

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

Weaknesses

CWE-306

Affected products

VendorProductAffected versions
honeywelliq4e_firmware< 3.30
honeywelliq4eall versions
honeywelliq412_firmware< 3.30
honeywelliq412all versions
honeywelliq422_firmware< 3.30
honeywelliq422all versions
honeywelliq4nc_firmware< 3.30
honeywelliq4ncall versions
honeywelliq41x_firmware< 3.30
honeywelliq41xall versions

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-3611