Vulnerability · Published May 11, 2026 · Assigned by runZero
CVE-2026-33356Meari MQTT broker missing per-device subscribe ACL
High 7.7
In plain English
A high-severity authorization bypass via user-controlled key in IoT Cloud MQTT Broker EMQX from Meari. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).
Severity (CVSS 3.1)7.7High
Exploit odds (30 days)0.3%top 80.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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 subscribe authorization at per-device scope.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Meari | IoT Cloud MQTT Broker EMQX | 4.x |
Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
References
- https://github.com/xn0tsa/nobody-puts-baby-in-a-corner technical-description
- https://www.runzero.com/advisories/meari-mqtt-broker-missing-per-device-subscribe-acl-cve-2026-33356/ third-party-advisory