CVE-2026-67412

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 4.3.3, 4.2.9 , 4.1.14, 4.0.24, and 3.13.18, Federation upstream in RabbitMQ skips vhost authorization allowing cross-vhost message access. what the bug lets you do. A policymaker on one vhost reads and drains messages out of another vhost it has no permission on. With the default ack-mode the source messages are consumed (deleted), not copied. Why that should not 1. Federation validates the upstream URI without any vhost-access Cross-vhost message read/drain from a per-vhost policymaker, breaking vhost tenancy This issue is fixed in versions 4.3.3, 4.2.9 , 4.1.14, 4.0.24, and 3.13.18.

• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-42pc-678q-v8qj
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-42pc-678q-v8qj