Auth bypass in Broadcom Rabbitmq Server
CVE-2026-66076
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (26.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
- Broadcom Rabbitmq Server
- Rabbitmq Rabbitmq-Server — versions >= 3.13.0, < 3.13.15, >= 4.0.0, < 4.0.20, >= 4.1.0, < 4.1.11
Weakness classification (CWE)
References
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 (Release Notes)
- github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-j45q-v7g2-82ph (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-66076?
- CVE-2026-66076 is a medium-severity vulnerability in Broadcom Rabbitmq Server, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-09-23.
- How severe is CVE-2026-66076?
- Medium severity. CVSS v3 base score is 6.5 out of 10.