Bug 2540087

Summary:	CVE-2026-66072 rabbitmq-server: RabbitMQ: Denial of Service via atom table exhaustion in stream chunk_selector [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Jon Weiser <jweiser>
Component:	rabbitmq-server	Assignee:	Peter Lemenkov <lemenkov>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	lemenkov, rjones
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["c7d78bfb-94a1-4b16-9b15-d92aae2673f8"]}
Fixed In Version:	rabbitmq-server-4.3.6-1.fc46 rabbitmq-server-4.3.6-1.fc45 rabbitmq-server-4.2.9-2.fc44	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-09 15:44:04 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2539758

Description Jon Weiser 2026-09-24 14:05:14 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.1, get_chunk_selector/1 calls binary_to_atom on the raw client-supplied <<"chunk_selector">> property from post-auth subscribe and resolve_offset_spec frames, with no whitelist and no existing guard. An authenticated stream client with read access to any stream can crash the broker node. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol user with read access to at least one stream. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.1.

Comment 1 Peter Lemenkov 2026-10-09 13:24:19 UTC

This issue is already fixed upstream in RabbitMQ 4.3.6, which is the version currently built for Fedora rawhide (rabbitmq-server-4.3.6-1.fc46) and Fedora 45 (rabbitmq-server-4.3.6-1.fc45).

Fedora 44 (currently 4.2.9) and Fedora 43 (currently 4.0.9) still need attention; backports/rebases for the still-supported stable branches are being worked on. Leaving this report open to track that remaining work.

Comment 2 Peter Lemenkov 2026-10-09 15:44:04 UTC

This issue is already addressed in the rabbitmq-server builds currently shipped in all maintained Fedora branches:

  * Fedora rawhide: rabbitmq-server-4.3.6-1.fc46
  * Fedora 45:      rabbitmq-server-4.3.6-1.fc45
  * Fedora 44:      rabbitmq-server-4.2.9-2.fc44

No new build is required for these branches, so closing as CURRENTRELEASE.

Fedora 43 (rabbitmq-server-4.0.9) will NOT be updated for this CVE batch: the upstream 4.0.x line ended at 4.0.9 (later 4.0.x fixes are commercial-only, with no public OSS release) and Fedora 43 reaches end of life on 2026-12-09, so a backport to F43 is not worthwhile.