How severe is CVE-2026-33356?

CVE-2026-33356 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-33356 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33356?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-33356 have an EU (EUVD) identifier?

Yes. CVE-2026-33356 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29102.

When was CVE-2026-33356 published?

CVE-2026-33356 was published on 2026-05-11 and last updated on 2026-06-17.

CVE-2026-33356

CVE-2026-33356 is a high-severity vulnerability with a CVSS 3.x base score of 7.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

Severity: High (CVSS 3.x base score 7.7)
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29102
Weakness: CWE-639
Published: 2026-05-11
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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 but does not enforce equivalent subscribe authorization at per-device scope.
How severe is CVE-2026-33356?: CVE-2026-33356 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-33356 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-33356?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-33356 have an EU (EUVD) identifier?: Yes. CVE-2026-33356 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29102.
When was CVE-2026-33356 published?: CVE-2026-33356 was published on 2026-05-11 and last updated on 2026-06-17.

References

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