CVE-2026-30867: CocoaMQTT is a MQTT 5.0 client library for iOS and macOS written in Swift

Q: How do I fix CVE-2026-30867?

cocoamqtt: upgrade to 2.2.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-30867 being exploited?

CVE-2026-30867 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-30867 affect?

CVE-2026-30867 affects cocoamqtt. Severity is medium (CVSS 5.7). 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

Q: How urgent is CVE-2026-30867?

Priority 31/100. Public exploit reference

Routine

MEDIUM 5.7UPGRADE

CVE-2026-30867 is a medium-severity flaw (CVSS 5.7) affecting cocoamqtt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 vulnerab

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.7 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-617
Published	2026-04-02
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: emqx

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-02 14:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

emqx cocoamqtt UPGRADE

Affected: < 2.2.2

Fixed in: 2.2.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cocoamqtt || rpm -q cocoamqtt || cocoamqtt --version

2. UPGRADE to 2.2.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cocoamqtt

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cocoamqtt

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-30867?

cocoamqtt: upgrade to 2.2.2. Exact commands for each OS are on this page.

Is CVE-2026-30867 being exploited?

CVE-2026-30867 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-30867 affect?

CVE-2026-30867 affects cocoamqtt. Severity is medium (CVSS 5.7). 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

How urgent is CVE-2026-30867?

Priority 31/100. Public exploit reference

Software pages

iOS vulnerabilities · macOS vulnerabilities · tvOS vulnerabilities · Swift vulnerabilities

References

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