Bug 2540085

Summary: CVE-2026-66070 rabbitmq-server: RabbitMQ: Cross-Origin Resource Sharing (CORS) misconfiguration allows unauthorized actions [fedora-all]
Product: [Fedora] Fedora Reporter: Jon Weiser <jweiser>
Component: rabbitmq-serverAssignee: Peter Lemenkov <lemenkov>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: lemenkov, rjones
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["1bc1c8a3-b430-4987-8b02-a7f6365b2c02"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2539724    

Description Jon Weiser 2026-09-24 14:05:03 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 3.13.17, 4.0.22, 4.1.13, and 4.2.6, match_origin/1 returned the bare reflected Origin and allowed credentials even when the wildcard "" was configured, so the response echoed the attacker's origin together with Access-Control-Allow-Credentials. The affected code is rabbit_mgmt_cors.erl. When the management plugin is configured with a wildcard CORS origin (cors_allow_origins = ""), the handler reflects the request Origin back in Access-Control-Allow-Origin and also sends Access-Control-Allow-Credentials: true. A malicious web page that a signed-in administrator visits can then use that administrator's cached HTTP Basic credentials to issue authenticated, state-changing requests to the management API. Preconditions include The management plugin is configured with the wildcard cors_allow_origins = "*", which is an explicit operator misconfiguration A target administrator has a cached HTTP Basic-auth session in the browser. This issue is fixed in versions 3.13.17, 4.0.22, 4.1.13, and 4.2.6.