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Fencer Vulns
high 7.5

CVE-2026-67232 json

RabbitMQ: Web-MQTT decompression bomb

published 2026-09-23 46 d ago modified 2026-10-20 19 d ago also BIT-rabbitmq-2026-67232 , EUVD-2026-85657 , GHSA-gmgx-hhg5-43gr

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami rabbitmq 3.13.15, 4.0.20, 4.1.11, 4.2.6
  • vmware rabbitmq 3.13.15, 4.0.20, 4.1.11, 4.2.6
  • pivotal_software rabbitmq 3.13.15, 4.0.20, 4.1.11, 4.2.6
  • rabbitmq-server Debian 14 4.3.0-2

debian advisories DEBIAN-CVE-2026-67232

  • rabbitmq-server Ubuntu 22.04 LTS 3.9.27-0ubuntu0.6
  • rabbitmq-server Ubuntu 24.04 LTS 3.12.1-1ubuntu1.7
  • rabbitmq-server Ubuntu 26.04 LTS 4.0.5-10ubuntu5.2
  • rabbitmq-server Ubuntu Pro 16.04 LTS 3.5.7-1ubuntu0.16.04.4+esm3
  • rabbitmq-server Ubuntu Pro 18.04 LTS 3.6.10-1ubuntu0.5+esm1
  • rabbitmq-server Ubuntu Pro 20.04 LTS 3.8.3-0ubuntu0.3+esm2

ubuntu advisories UBUNTU-CVE-2026-67232

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rabbitmq-server4.3 hummingbird 1 4.3.6-1.hum1

red hat advisories RHSA-2026:67552

  • rabbitmq-server Azure Linux 3.0 3.13.7-10

azure linux advisories AZL-105795

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-67232 updated cvss 7.5

rabbitmq: rabbitmq_web_mqtt: RabbitMQ Web-MQTT plugin: Denial of Service via decompression bomb

  • Red Hat Hardened Images rabbitmq-server4.2 4.2.9-0.2.hum1
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Hardened Images rabbitmq-server4.3 4.3.6-1.hum1
    fixed: vendor fix RHSA-2026:67552

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
45 d ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami rabbitmq
>=3.13.0, <3.13.15
>=4.0.0, <4.0.20
>=4.1.0, <4.1.11
>=4.2.0, <4.2.6
3.13.15
4.0.20
4.1.11
4.2.6

Affected products

  • rabbitmq rabbitmq-server

Classification

Weakness
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.