Home/CVE/CocoaMQTT is a MQTT 5.0 client library for iOS and macOS written in Swift. Prior to version 2.2.2, a vulnerability exist
CVE
CVE-2026-308671
CocoaMQTT is a MQTT 5.0 client library for iOS and macOS written in Swift. Prior to version 2.2.2, a vulnerability exist
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.
MEDIUM · CVSS 5.7
EPSS 0.00017
EPSS exploitation odds0.02% · top 95%
Schedule remediation
- Public exploit or PoC is available
Sigma rules8
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-30867, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
EPSS exploitation probability
0.02%
Top 95%odds of exploitation in the next 30 days
CVSS metric silhouette
shape grows toward worst-case
CVSS vector breakdown
Exploitability - how they get in
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Impact - what breaks
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
VECTOR
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:HLifecycle
- 02 Apr 2026Published to NVD
- 07 Apr 2026Last modified
Every entry is a recorded date - NVD publish/modify, CISA KEV add, public exploit disclosure. No inferred events.
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Public Exploits & PoCs
1These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted. Signed-in users mark whether it works, rate 1-10, and can report malware with a required reason that becomes a public comment.
Works?
no reports yet
Rating
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ATT&CK techniques
1Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.
▤ Build a SIEM detection for these techniques⬡
Weakness Classification
CWE-617Reachable Assertion
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Affected Products & Versions
1emqx cocoamqtt< 2.2.2
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Affected Packages
1Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
SwiftURL
CocoaMQTT
MEDIUM
fixed in 2.2.2
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Related CVEs
8CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-2006-4095
BIND before 9.2.6-P1 and 9.3.x before 9.3.2-P1 allows remote attackers to cause ...
same CWE-617
HIGH
CVE-2006-4574
Off-by-one error in the MIME Multipart dissector in Wireshark (formerly Ethereal...
same CWE-617
HIGH
CVE-2006-5779
OpenLDAP before 2.3.29 allows remote attackers to cause a denial of service (dae...
same CWE-617
HIGH
CVE-2006-6811
KsIRC 1.3.12 allows remote attackers to cause a denial of service (crash) via a ...
same CWE-617
MEDIUM
CVE-2010-1752
Stack-based buffer overflow in CFNetwork in Apple iOS before 4 on the iPhone and...
same product
CVE-2010-1753
ImageIO in Apple iOS before 4 on the iPhone and iPod touch allows remote attacke...
same product
CVE-2010-1754
Passcode Lock in Apple iOS before 4 on the iPhone and iPod touch does not proper...
same product
CVE-2010-1755
Safari in Apple iOS before 4 on the iPhone and iPod touch does not properly impl...
same product
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Sigma Hunt Rules
8Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSuspicious Microsoft Office Child Process - MacOS
producthighRemote Access Tool - Renamed MeshAgent Execution - MacOS
producthighBinary Padding - MacOS
productmediumSuspicious Execution via macOS Script Editor
productmediumSystem Information Discovery Via Sysctl - MacOS
productmediumNew File Exclusion Added To Time Machine Via Tmutil - MacOS
productmediumSuspicious MacOS Firmware Activity
productmediumDisk Image Mounting Via Hdiutil - MacOS
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References & Sources
3Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.