CVE-2026-57218 in Server
Summary
by MITRE • 07/10/2026
RabbitMQ is a messaging and streaming broker. Prior to 4.2.6, RabbitMQ AMQP 0-9-1 allows an existing consumer to keep receiving messages after OAuth token expiry or connection.update_secret refresh to reduced scopes because existing consumers are not canceled or reauthorized at delivery time after the channel user state changes. This issue is fixed in version 4.2.6.
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Analysis
by VulDB Data Team • 07/10/2026
This vulnerability affects RabbitMQ messaging brokers that implement the AMQP 0-9-1 protocol and represents a critical authorization bypass flaw that undermines the security of OAuth-based authentication systems. The issue occurs when consumers maintain their ability to receive messages even after their authentication tokens have expired or when connection secrets are updated to reduced scopes, creating a persistent security gap where unauthorized access can occur through existing consumer channels.
The technical root cause lies in how RabbitMQ handles channel user state changes during authentication token expiration or secret updates. When an OAuth token expires or connection.update_secret is called to reduce scopes, the system fails to properly invalidate existing consumers that were established under the previous authentication state. This design flaw means that consumers continue operating with their original authorization context while the underlying authentication mechanism has already been updated or revoked.
The operational impact of this vulnerability extends beyond simple unauthorized message access to encompass potential data leakage and privilege escalation scenarios within messaging systems. An attacker who can manipulate the OAuth token lifecycle or connection secrets could maintain access to sensitive message queues through existing consumers, potentially allowing for continuous data exfiltration or manipulation of message flows. This particularly affects environments where message brokers handle confidential information or where strict access control policies must be enforced.
Security practitioners should note that this vulnerability aligns with CWE-284 Access Control Issues and represents a failure in proper authorization state management during authentication updates. The issue also corresponds to ATT&CK technique T1566 Privilege Escalation through the maintenance of elevated privileges via compromised consumer sessions. Organizations implementing RabbitMQ in environments requiring robust security controls must prioritize immediate upgrade to version 4.2.6 or later, as the fix addresses the core problem of consumer authorization state synchronization with authentication updates.
The vulnerability demonstrates a fundamental gap in session management within messaging systems where consumer lifecycle management does not properly synchronize with authentication state changes. This creates persistent access windows that can be exploited even after legitimate authentication mechanisms have been updated or revoked. The fix implemented in version 4.2.6 ensures that when channel user states change due to token expiration or scope reduction, existing consumers are properly invalidated or reauthorized at delivery time, preventing the continuation of unauthorized message consumption.
Organizations should also consider implementing additional monitoring and alerting for authentication state changes and consumer behavior patterns that might indicate exploitation attempts. The vulnerability affects systems where RabbitMQ serves as a central messaging infrastructure component in distributed applications, making it particularly relevant for enterprise environments, cloud deployments, and microservices architectures where secure message passing is critical. Proper security configuration management including regular authentication token rotation and connection secret updates becomes essential when operating with versions prior to 4.2.6.
This issue highlights the importance of comprehensive authorization state management in distributed systems where multiple authentication mechanisms interact with consumer sessions. The vulnerability serves as a reminder that authentication updates must propagate properly throughout the entire system session lifecycle rather than creating isolated state inconsistencies that can be exploited by attackers maintaining access through existing consumer channels. Security teams should conduct thorough assessments of their RabbitMQ deployments to identify and remediate any instances operating below version 4.2.6 where this vulnerability may exist.