Bug 2541518 (CVE-2026-67226)

Summary:	CVE-2026-67226 rabbitmq-server: rabbitmq-server: Denial of Service via Erlang atom exhaustion in user tag management
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in rabbitmq-server. An authenticated user with administrative privileges can cause a Denial of Service (DoS) by submitting user definitions containing an excessive number of unique tag names. Because the application converts each tag string into an internal Erlang identifier that cannot be cleared from memory, the atom table is exhausted and crashes the broker node.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-09-25 16:51:58 UTC

RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7, Admin-only atom exhaustion: PUT /api/users tags list. settags/2 maps rabbitdatacoercion:toatom/1 over the user's tags list. The 20 MB management body limit fits ~3-4M short tag strings. An administrator can crash the node in a single request by creating a user (or importing definitions) with ~1M unique tag administrator. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7.