An authenticated low-privilege user can trigger a cross-tenant denial of service condition in RabbitMQ by sending arbitrary JMS selector strings to an x-jms-topic exchange.

This is an uncontrolled resource consumption flaw (CWE-400) where the server fails to enforce length constraints on JMS selector strings. An authenticated AMQP user with read access to an x-jms-topic exchange can force the broker to intern excessive atom literals, exhausting memory and crashing the node.

Successful exploitation allows an authenticated user to perform a cross-tenant denial of service, rendering the messaging broker unavailable for all users on the affected node. While the CVSS score is 6.0, the impact on business continuity is significant for environments relying on RabbitMQ for critical message queuing and streaming operations.

Immediate Action: Update rabbitmq-server to version 3.13.15, 4.0.20, 4.1.11, 4.2.6, or 4.3.0 immediately.

Proactive Monitoring: Monitor RabbitMQ logs and system resource usage, specifically tracking atom count and memory consumption for signs of anomalous increases following binding operations.

Compensating Controls: Ensure strict access control lists (ACLs) are enforced for AMQP users to restrict read/write permissions on sensitive exchanges and queues, limiting the potential pool of attackers.

Public Exploit Available: Unknown

Given the ability for a low-privileged user to crash an entire broker node, organizations should prioritize upgrading RabbitMQ to the specified fixed versions. Administrative teams should audit current user permissions to ensure that only authorized accounts possess the required read and write capabilities on JMS topic exchanges until patches are applied.