What is CVE-2026-33356?

CVE-2026-33356 is a high-severity vulnerability in Meari Iot Cloud Mqtt Broker Emqx, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.7/10. Published 2026-05-11.

How severe is CVE-2026-33356?

High severity. CVSS v3 base score is 7.7 out of 10.

Auth bypass in Meari Iot Cloud Mqtt Broker Emqx

CVE-2026-33356

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…

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.000 (1.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N.

Affected products

Meari Iot Cloud Mqtt Broker Emqx — versions 4.x

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

44488dab-36db-4358-99f9-bc116477f914 (technical-description)
44488dab-36db-4358-99f9-bc116477f914 (third-party-advisory)

Frequently asked questions

What is CVE-2026-33356?: CVE-2026-33356 is a high-severity vulnerability in Meari Iot Cloud Mqtt Broker Emqx, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.7/10. Published 2026-05-11.
How severe is CVE-2026-33356?: High severity. CVSS v3 base score is 7.7 out of 10.