Auth bypass in Broadcom Rabbitmq Server
CVE-2026-67241
RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.9 and 4.3.3, AMQP 1.0 management exchange.declare skips alternate-exchange permission check. pUT /exchanges/:name (lines 192-240) checks only configure on the declared exchange and passes XArgs straight to rabbitexchange:declare/7. It omits the checkreadpermitted(X) + checkwritepermitted(AE) that rabbitchannel.erl:2540-2548 enforces for the alternate-exchange argument on the AMQP 0-9-1 path. The same file already implements the analogous DLX check for queues (lines 708-719), confirming this is a missing-check bug rather than intentional A user with only configure on exchange X can route X's unroutable messages into an alternate exchange they have no write permission AMQP 1.0 enabled (default in RabbitMQ 4.x) Attacker has configure on at least one exchange but lacks write on the target. This issue is fixed in versions 4.2.9 and 4.3.3.
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:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (37.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.1% 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: 0.004 · change: +0.001
Affected products
- Broadcom Rabbitmq Server
- Rabbitmq Rabbitmq-Server — versions >= 4.2.0, < 4.2.9, >= 4.3.0, < 4.3.3
Weakness classification (CWE)
References
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-rg2g-289m-xhhw (Vendor Advisory)
- https://github.com/rabbitmq/rabbitmq-server/commit/18eac8d547b4382bf830c621b20a35932dd1cfa5 (Patch)
- https://github.com/rabbitmq/rabbitmq-server/commit/56005e7cebffc478ef397573de24aff1167e7cda (Patch)
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9 (Release Notes)
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3 (Release Notes)
Frequently asked questions
- What is CVE-2026-67241?
- CVE-2026-67241 is a medium-severity vulnerability in Broadcom Rabbitmq Server, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-09-25.
- How severe is CVE-2026-67241?
- Medium severity. CVSS v3 base score is 6.5 out of 10.