Cyber Resilience

CVE-2026-33356

High

Published: 11 May 2026

Published
11 May 2026
Modified
13 May 2026
KEV Added
—
Patch
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CVSS Score v3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
EPSS Score 0.0001 1.7th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-33356 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Runzero (inferred from references). Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 1.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

In Meari IoT Cloud MQTT Broker deployments running EMQX 4.x, any authenticated low-privilege account can subscribe to global wildcard topics and receive telemetry from devices the user does not own. The broker enforces publish restrictions but does not enforce equivalent…

more

subscribe authorization at per-device scope.

CWE(s)
CWE-639

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

Authorization bypass in public-facing MQTT broker directly enables exploitation of the application for unauthorized data access.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2024-50693Shared CWE-639
CVE-2025-69394Shared CWE-639
CVE-2026-41471Shared CWE-639
CVE-2025-58402Shared CWE-639
CVE-2025-68051Shared CWE-639
CVE-2026-4503Shared CWE-639
CVE-2026-43890Shared CWE-639
CVE-2026-25563Shared CWE-639
CVE-2024-8261Shared CWE-639
CVE-2026-3321Shared CWE-639

Affected Assets

Runzero
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inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-24 Access Control Decisions
addresses: CWE-639

Per-request decision making makes it harder to bypass authorization using user-controlled keys without proper validation in the decision process.

AC-3 Access Enforcement
addresses: CWE-639

Consistent enforcement of approved authorizations makes bypassing via user-controlled keys ineffective.

References