Subscriber disconnection via unchecked PUBLISH property
Published Oct 14, 2026 · Updated Oct 14, 2026
Input validation in RabbitMQ Server's MQTT 5 parser allows remote authenticated users to disconnect subscribers via malformed PUBLISH packets. The rabbit_mqtt_packet.erl parser accepts the CONNECT-only Request-Problem-Information property on PUBLISH packets and routes it to subscribers, where serialise_prop/2 raises an uncaught function_clause exception. MQTT must be enabled, the publisher must have topic write permission, and a separately authenticated MQTT or Web MQTT subscriber must match that topic; the subscriber connection closes while the publisher connection and broker remain available.
Summary
What happened
Input validation in RabbitMQ Server's MQTT 5 parser allows remote authenticated users to disconnect subscribers via malformed PUBLISH packets. The rabbit_mqtt_packet.erl parser accepts the CONNECT-only Request-Problem-Information property on PUBLISH packets and routes it to subscribers, where serialise_prop/2 raises an uncaught function_clause exception. MQTT must be enabled, the publisher must have topic write permission, and a separately authenticated MQTT or Web MQTT subscriber must match that topic; the subscriber connection closes while the publisher connection and broker remain available.
The record
- CVE
- CVE-2026-67418
- Published
- Oct 14, 2026
- Updated
- Oct 14, 2026
- Vendor
- RabbitMQ
- Product
- RabbitMQ Server
- Classifications
- CWE-1286, CWE-248, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 14, 2026CVE publishedPublication date reported by the CVE source.
- Oct 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 3.13.0, < 3.13.19
- Affected versionversion=>= 4.0.0, < 4.0.24
- Affected versionversion=>= 4.1.0, < 4.1.15
- Affected versionversion=>= 4.2.0, < 4.2.10
- Affected versionversion=>= 4.3.0, < 4.3.5
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Upstream two-client MQTT subscriber-disconnection proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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