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Fencer Vulns
high 7.5

CVE-2026-66079 json

RabbitMQ: Pre-auth AMQP 1.0 array32 zero-width element DoS

published 2026-09-23 46 d ago modified 2026-10-20 19 d ago also BIT-rabbitmq-2026-66079 , EUVD-2026-85627 , GHSA-c66h-hf5j-8jf9

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
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, and 4.2.6, parse_array_primitive/2 for constructor 0x45 (list0) returns an element with byte-width B = 0. The enclosing array32 parser at line 148 reads a 4-byte Count from the wire and loops Count times consuming B bytes each , with B = 0, no input is consumed and the loop builds a list of Count empty elements bounded only by the 32-bit field. The SASL-mechanisms / SASL-init frame is parsed by amqp10_framing:decode_bin/1 from rabbit_amqp_reader.erl:412 before authentication completes. The pre-auth incoming_max_frame_size (default 8192 bytes) caps the frame, not the Count field, so a 19-byte payload with Count = 0xFFFFFFFF is accepted. No max_heap_size is set on the reader process. An unauthenticated network attacker can crash any RabbitMQ node that has the AMQP 1.0 listener enabled (default port 5672) by sending a single ~19-byte frame. The reader process attempts to build a list of ~4 billion empty elements, exhausting heap memory and terminating the Erlang VM. All tenants and protocols on the node lose service. Preconditions include Network reachability to the AMQP listener (port 5672, enabled by default) No authentication required. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

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-2026-66079

  • 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-2026-66079

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-105744

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-2026-66079 updated cvss 7.5

rabbitmq-server: RabbitMQ: Denial of Service via AMQP 1.0 array32 parsing

  • Red Hat Hardened Images rabbitmq-server4.2 4.2.9-0.2.hum1
    affected: workaround, no fix planned “Restrict untrusted network access to AMQP listeners; disable AMQP 1.0 support if unused.”
  • Red Hat Hardened Images rabbitmq-server4.3 4.3.6-1.hum1
    fixed: vendor fix “Restrict untrusted network access to AMQP listeners; disable AMQP 1.0 support if unused.” RHSA-2026:67552
  • Red Hat OpenStack Platform 13 (Queens) rabbitmq-server Red Hat OpenStack Platform 16.2 rabbitmq-server Red Hat OpenStack Platform 17.1 rabbitmq-server
    not affected: vulnerable code not present
  • Red Hat OpenStack Platform 18.0 rabbitmq-server
    not affected: vulnerable code not in execute path

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
yes
Technical impact
partial
Assessed
41 d ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% 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-770 Allocation of Resources Without Limits or Throttling

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.