The vulnerability is a flaw in RabbitMQ Federation where the upstream configuration bypasses virtual‑host authorization checks, allowing a policymaker with permissions on one virtual host to read and drain messages from another virtual host for which it has no rights. This can lead to confidentiality leaks and unwanted data loss because the default acknowledgement mode consumes the source messages rather than merely copying them. The weakness is exemplified by CWE-639, a privilege and authorization elevation through separation of duties, and CWE-862, an improper use of authorization controls.

RabbitMQ Server versions 3.13.0 through 4.3.3 are affected, specifically the releases 3.13.0, 3.13.18, 4.0.24, 4.1.14, 4.2.9, and 4.3.3.

The CVSS score of 6.0 indicates a moderate severity. Indications of exploitation are not formally reported (EPSS not provided and no KEV listing). The attack likely requires that the attacker has policy‑level access to a federation upstream; once that condition is met, it can read or delete cross‑vhost messages. The impact is limited to message confidentiality and integrity, not to system compromise.