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Vulnerabilities

Vulnerability · CVE-2026-67232

RabbitMQ: Web-MQTT decompression bomb

Published Sep 23, 2026 · catalog updated Sep 24, 2026 · RabbitMQ: Web-MQTT decompression bomb

Check if you run it

No confirmed exploitation is on record for CVE-2026-67232. EPSS is 0.37%. Act only if a listed version of RabbitMQ: Web-MQTT decompression bomb is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (RabbitMQ: Web-MQTT decompression bomb).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.37%
Remediation
Advisory link
Affected products
vendor rabbitmq rabbitmq-server

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

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  • vendor rabbitmq rabbitmq-serverversion unspecified

How to fix CVE-2026-67232

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-67232. EPSS is 0.37%. Act only if a listed version of RabbitMQ: Web-MQTT decompression bomb is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-409. EPSS 0.37%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ubuntu security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 24, 2026 · CVE.org

    Updated

    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

  2. Oct 15, 2026 · Ubuntu Security Notices

    Detected

    CVE-2026-67232 is listed by USN-8933-1: RabbitMQ Server vulnerabilities.

Sources

  • CVE.orgVulnerability recordCVE-2026-67232

    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

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-67232

    30-day exploitation probability 0.4%

    first.org
  • Ubuntu Security NoticesVendor advisoryCVE-2026-67232

    It was discovered that RabbitMQ Server incorrectly handled CORS wildcard origin configuration. An attacker could possibly use this issue to cause a cross-site request forgery attack. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,

    ubuntu.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.