Bug 2539787 (CVE-2026-67232) - CVE-2026-67232 rabbitmq: rabbitmq_web_mqtt: RabbitMQ Web-MQTT plugin: Denial of Service via decompression bomb
Summary: CVE-2026-67232 rabbitmq: rabbitmq_web_mqtt: RabbitMQ Web-MQTT plugin: Denial ...
Keywords:
Status: NEW
Alias: CVE-2026-67232
Product: Security Response
Classification: Other
Component: vulnerability-draft
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
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Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-23 20:53 UTC by OSIDB Bzimport
Modified: 2026-09-23 21:00 UTC (History)
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Description OSIDB Bzimport 2026-09-23 20:53:19 UTC
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.


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