cvedb.io
CVE-2026-30867
MEDIUM · CVSS 5.7
EPSS exploitation probability: 0%
Published 2026-04-02T14:16:28.407 · Last modified 2026-06-17T10:33:03.470

Summary

CocoaMQTT is a MQTT 5.0 client library for iOS and macOS written in Swift. Prior to version 2.2.2, a vulnerability exists in the packet parsing logic of CocoaMQTT that allows an attacker (or a compromised/malicious MQTT broker) to remotely crash the host iOS/macOS/tvOS application. If an attacker publishes the 4-byte malformed payload to a shared topic with the RETAIN flag set to true, the MQTT broker will persist the payload. Any time a vulnerable client connects and subscribes to that topic, the broker will automatically push the malformed packet. The app will instantly crash in the background before the user can even interact with it. This effectively "bricks" the mobile application (a persistent DoS) until the retained message is manually wiped from the broker database. This issue has

Affected products

emqx — cocoamqtt

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.