{"id":"CVE-2026-67411","state":"PUBLISHED","title":"RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass","description":"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.","publishedAt":"2026-09-25T16:26:33.880Z","updatedAt":"2026-09-25T16:55:42.722Z","severity":{"score":6,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["rabbitmq rabbitmq-server"],"affected":[{"vendor":"rabbitmq","product":"rabbitmq-server","versions":[{"version":">= 4.3.0, < 4.3.3","status":"affected"},{"version":">= 4.2.0, < 4.2.9","status":"affected"},{"version":">= 4.1.0, < 4.1.14","status":"affected"},{"version":">= 4.0.0, < 4.0.23","status":"affected"},{"version":">= 3.13.0, < 3.13.18","status":"affected"}]}],"references":["https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6","https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349","https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646","https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9","https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/67xxx/CVE-2026-67411.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-67411","state":"PUBLISHED","datePublished":"2026-09-25T16:26:33.880Z","dateUpdated":"2026-09-25T16:55:42.722Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-29T15:02:20.412Z"},"containers":{"cna":{"title":"RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"rabbitmq","product":"rabbitmq-server","versions":[{"version":">= 4.3.0, < 4.3.3","status":"affected"},{"version":">= 4.2.0, < 4.2.9","status":"affected"},{"version":">= 4.1.0, < 4.1.14","status":"affected"},{"version":">= 4.0.0, < 4.0.23","status":"affected"},{"version":">= 3.13.0, < 3.13.18","status":"affected"}]}],"references":[{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6","name":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349","name":"https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349","tags":["x_refsource_MISC"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646","name":"https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646","tags":["x_refsource_MISC"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9","name":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9","tags":["x_refsource_MISC"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3","name":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863: Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-25T16:26:33.880Z"},"source":{"advisory":"GHSA-4r6f-9cpw-f6g6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-25T16:55:11.064286Z","id":"CVE-2026-67411","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-25T16:55:42.722Z"}}]}}}