Bug 2539724 (CVE-2026-66070)

Summary: CVE-2026-66070 rabbitmq-server: RabbitMQ: Cross-Origin Resource Sharing (CORS) misconfiguration allows unauthorized actions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in RabbitMQ. When the management plugin is configured with a wildcard Cross-Origin Resource Sharing (CORS) origin, it incorrectly reflects the attacker's origin and allows credentials. This vulnerability enables a malicious web page to leverage a signed-in administrator's cached credentials. Consequently, an attacker can issue authenticated requests to the management API, potentially leading to unauthorized actions.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2540085    
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Description OSIDB Bzimport 2026-09-23 20:12:52 UTC 
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.