NVD / CVE Program· CNA icscert

CVE-2026-3611: Honeywell IQ4x BMS Controller Missing authentication for critical function

Noroxi assessment

Priority: Plan (action score 42/100)

Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 5.7% (FIRST EPSS); higher than 93% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
According to the record, no fixed version is available yet.

Add it to your regular patch cycle. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 10.0 · v4.0—Proof of concept No fix recorded

BDU:2026-09910

Published: Mar 12, 2026
Updated: Jun 17, 2026
EPSS: 5.7% · 93th percentile
CWE: CWE-306

Report tools

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Action score

Plan

Add it to your regular patch cycle.

CVSS: 40 / 40 · 10.0 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 2 / 30 · 5.7%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · icscert: 10.0; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
honeywell	iq4e firmware	cpe:2.3:o:honeywell:iq4e_firmware
honeywell	iq4e	cpe:2.3:h:honeywell:iq4e
honeywell	iq412 firmware	cpe:2.3:o:honeywell:iq412_firmware
honeywell	iq412	cpe:2.3:h:honeywell:iq412
honeywell	iq422 firmware	cpe:2.3:o:honeywell:iq422_firmware
honeywell	iq422	cpe:2.3:h:honeywell:iq422
honeywell	iq4nc firmware	cpe:2.3:o:honeywell:iq4nc_firmware
honeywell	iq4nc	cpe:2.3:h:honeywell:iq4nc
honeywell	iq41x firmware	cpe:2.3:o:honeywell:iq41x_firmware
honeywell	iq41x	cpe:2.3:h:honeywell:iq41x

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

honeywell iq412 firmwarebefore 3.30
honeywell iq41x firmwarebefore 3.30
honeywell iq422 firmwarebefore 3.30
honeywell iq4e firmwarebefore 3.30
honeywell iq4nc firmwarebefore 3.30

Versions reported by the vendor

Affected version ranges reported by the assigning authority (icscert). Independent of NVD's CPE analysis and usually ahead of it.

Honeywell IQ3
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQ412
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQ41x
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQ422
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQ4E
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQ4NC
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected
Honeywell IQECO
- v3.50_3.44 and later · up to and including 4.36 (build 4.3.7.9)affected

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:1	2026-08-03

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedMar 12, 2026
First PoCAug 3, 2026+143 d
TodayNov 7, 2026+240 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Gjoko KrsticZero Sciencefinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

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

nvd-secondary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1// Added for the support team
2app.post("/maintenance/reset", resetDevice);

Fixed

1if (config.maintenanceEnabled) {
2  app.post(
3    "/maintenance/reset",
4    requireSession, requireRole("admin"), resetDevice
5  );
6}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-069-03.json

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records