CVE-2026-30867

5.7 MEDIUM
Published: April 02, 2026 Modified: April 07, 2026
View on NVD

Description

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 been patched in version 2.2.2.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/emqx/CocoaMQTT/pull/659
Source: security-advisories@github.com
Issue Tracking Patch
https://github.com/emqx/CocoaMQTT/releases/tag/2.2.2
Source: security-advisories@github.com
Release Notes
https://github.com/emqx/CocoaMQTT/security/advisories/GHSA-r3fr-7m74-q7g2
Source: security-advisories@github.com
Exploit Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.7 / 10.0
EPSS (Exploit Probability)
0.0%
14th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

emqx apple