CVE-2026-67412: RabbitMQ: Federation upstream skips vhost authorization allowing cross-vhost message access

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-09-25 · updated 2026-10-08
Weakness: CWE-862

Description

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.

Affected products

rabbitmq-server: from 3.13.0 before 3.13.18; from 4.0.0 before 4.0.24; from 4.1.0 before 4.1.14; from 4.2.0 before 4.2.9; from 4.3.0 before 4.3.3 — fixed in 3.13.18, 4.0.24, 4.1.14, 4.2.9, 4.3.3

How to fix

Upgrade to a fixed version: rabbitmq-server 3.13.18, 4.0.24, 4.1.14, 4.2.9. Check the vendor advisory for mitigations.

References

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