Bug 2539757 (CVE-2026-66080)

Summary:	CVE-2026-66080 rabbitmq-server: RabbitMQ: Denial of Service via unbounded super-stream partition allocation
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in RabbitMQ. A highly privileged remote attacker, with the `rabbitmq_stream_management` plugin enabled and access to the target vhost, can exploit an unbounded allocation vulnerability in the super-stream partitions. This allows the attacker to allocate a large amount of memory, leading to a Denial of Service (DoS) due to resource exhaustion.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2540094
Bug Blocks:

Description OSIDB Bzimport 2026-09-23 20:32:29 UTC

RabbitMQ is a messaging and streaming broker. Prior to versions 4.1.11, 4.2.6, and 4.3.0, validate_partitions only checks that the requested partition count is at least 1, with no upper bound. A large count such as lists:seq(0, 500000000) allocates roughly 8GB. Preconditions include The rabbitmq_stream_management plugin must be enabled. The caller needs the management tag and access to the target vhost.. This issue is fixed in versions 4.1.11, 4.2.6, and 4.3.0.