CVE-2026-66079 RabbitMQ: Pre-auth AMQP 1.0 array32 zero-width element DoS

What is CVE-2026-66079?

CVE-2026-66079 is a high-severity vulnerability in Broadcom Rabbitmq Server, published on 23 Sep 2026.

Official description

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.

Weakness: CWE-770

Which versions are affected by CVE-2026-66079?

1 open source package ship an affected version, including rabbitmq. It affects 1 product.

Products include Broadcom Rabbitmq Server.

How do I fix CVE-2026-66079?

Upgrade rabbitmq to a fixed version for your release line: 3.13.15, 4.0.20, 4.1.11 or 4.2.6.

Is CVE-2026-66079 being exploited?

There is no known exploitation of CVE-2026-66079 in the wild and no public exploit code.

Other vulnerabilities in Broadcom Rabbitmq Server

• CVE-2016-9877 Auth bypass in Pivotal RabbitMQ 3.x before 3.5.8 and 3.6.x before 3.6.6; RabbitMQ for PCF 1.5.x before 1.5.20, 1.6.x before 1.6.12 and 1.7.x before 1.7.7 Critical 9.8
• CVE-2026-67404 RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch Critical 9.2
• CVE-2026-67231 RabbitMQ: Trust-store whitelist by Issuer+Serial only Critical 9.1
• CVE-2026-57219 Information disclosure in rabbitmq-server High 8.7
• CVE-2026-67236 RabbitMQ: Plaintext username:password stored in an insecure cookie after successful POST /login High 8.2

All Broadcom Rabbitmq Server vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-105744, BIT-rabbitmq-2026-66079, DEBIAN-CVE-2026-66079, GHSA-c66h-hf5j-8jf9, UBUNTU-CVE-2026-66079.