RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, The cowboy WebSocket options at line 117 set compress => true, enabling RFC 7692 permessage-deflate negotiation. The handler does not set max_frame_size, so cowboy's default of infinity applies. cowlib's cow_ws:parse_payload/9 calls zlib:inflate/2 on the compressed payload with no output-size limit. An attacker can negotiate permessage-deflate during the WebSocket upgrade and send a frame containing a zlib bomb (e.g. 50 KB → 5 GB). Decompression occurs in the connection process before websocket_handle/2 ever sees the MQTT bytes. An unauthenticated attacker can crash a RabbitMQ node running the Web-MQTT plugin by sending a single highly-compressed WebSocket frame (a few KB on the wire) that inflates to gigabytes in memory. The cowboy WebSocket handler decompresses the entire frame before the MQTT CONNECT packet is processed, so no credentials are required. Preconditions include rabbitmq_web_mqtt plugin enabled (not default, but common for browser clients) Network reachability to port 15675/15676 No authentication required. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.
References
| Link | Resource |
|---|---|
| https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 | Release Notes |
| https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0 | Release Notes |
| https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-gmgx-hhg5-43gr | Vendor Advisory |
Configurations
Configuration 1 (hide)
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History
19 Oct 2026, 20:39
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:* | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.5 |
| First Time |
Broadcom rabbitmq Server
Broadcom |
|
| References | () https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 - Release Notes | |
| References | () https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0 - Release Notes | |
| References | () https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-gmgx-hhg5-43gr - Vendor Advisory |
23 Sep 2026, 21:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-23 21:17
Updated : 2026-10-19 20:39
NVD link : CVE-2026-67232
Mitre link : CVE-2026-67232
CVE.ORG link : CVE-2026-67232
JSON object : View
Products Affected
broadcom
- rabbitmq_server
CWE
CWE-409
Improper Handling of Highly Compressed Data (Data Amplification)
