{"id":"BIT-rabbitmq-2026-67411","summary":"RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass","details":"RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3, native MQTT and MQTT over WebSocket behind a trusted PROXY Protocol frontend could lose the proxy-derived client address before the MQTT authentication path checked loopback_users, causing the frontend-to-broker address to be treated as loopback. An attacker who can reach the trusted frontend and has valid credentials for a loopback-restricted account can therefore bypass the source-address restriction; the issue does not bypass password authentication. This issue is fixed in versions 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3.","aliases":["CVE-2026-67411","GHSA-4r6f-9cpw-f6g6"],"modified":"2026-10-09T12:00:13.806439031Z","published":"2026-10-01T09:33:52.137Z","database_specific":{"severity":"High","cpes":["cpe:2.3:a:vmware:rabbitmq:*:*:*:*:*:*:*:*"]},"references":[{"type":"FIX","url":"https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349"},{"type":"FIX","url":"https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646"},{"type":"ARTICLE","url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9"},{"type":"ARTICLE","url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3"},{"type":"ADVISORY","url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67411"}],"affected":[{"package":{"name":"rabbitmq","ecosystem":"Bitnami","purl":"pkg:bitnami/rabbitmq"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.13.0"},{"fixed":"3.13.18"},{"introduced":"4.0.0"},{"fixed":"4.0.23"},{"introduced":"4.1.0"},{"fixed":"4.1.14"},{"introduced":"4.2.0"},{"fixed":"4.2.9"},{"introduced":"4.3.0"},{"fixed":"4.3.3"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/rabbitmq/BIT-rabbitmq-2026-67411.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"}]}],"schema_version":"1.9.0"}