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.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.7, indicating it can be exploited remotely over the network with relatively low complexity though user interaction is required requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 3 products from emqx, from apple, from apple organizations running these solutions should prioritize assessment and patching.
Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2026-04-02T14:16:28.407
2026-04-07T18:04:00.657
Analyzed
CVSSv3.1: 5.7 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | emqx | cocoamqtt | < 2.2.2 | Yes |
| Operating System | apple | iphone_os | - | No |
| Operating System | apple | macos | - | No |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For emqx's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.