# CVE-2026-66076: RabbitMQ: Cross-vhost quorum-queue status and stream tracking disclosure

CVE-2026-66076 is fixed in rabbitmq-server on 1 platform by DEBIAN-CVE-2026-66076 (version 4.3.0-2), released September 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66076
- Priority: Routine
- CVSS: 6.5 (Low)
- EPSS: 0.0033
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 23, 2026
- Weakness: Missing Authorization
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66076

## Description

RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, is_authorized/2 calls rabbit_mgmt_util:is_authorized/2, which checks only the management tag, instead of is_authorized_vhost/2. The /api/queues/quorum/:vhost/:queue/status handler reads the vhost from the path without checking that the user can access it. Any management-tagged user can therefore read Raft status, including leader, members, term, and commit index, for quorum queues in inaccessible vhosts, exposing cross-tenant queue names and cluster topology. The management plugin must be enabled and the attacker must have a management tag. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | rabbitmq-server Debian 14 | 4.3.0-2 | [DEBIAN-CVE-2026-66076](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66076.md) | Sep 25, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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