{"id":"CVE-2026-66067","state":"PUBLISHED","title":"RabbitMQ: Stream protocol skips per vhost per user connection limits","description":"RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1.","publishedAt":"2026-09-23T20:12:00.076Z","updatedAt":"2026-09-24T14:11:44.566Z","severity":{"score":6,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["rabbitmq rabbitmq-server"],"affected":[{"vendor":"rabbitmq","product":"rabbitmq-server","versions":[{"version":">= 4.2.0, < 4.2.7","status":"affected"},{"version":">= 4.3.0, < 4.3.1","status":"affected"}]}],"references":["https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf","https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7","https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/66xxx/CVE-2026-66067.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-66067","state":"PUBLISHED","datePublished":"2026-09-23T20:12:00.076Z","dateUpdated":"2026-09-24T14:11:44.566Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-23T23:25:28.897Z"},"containers":{"cna":{"title":"RabbitMQ: Stream protocol skips per vhost per user connection limits","descriptions":[{"lang":"en","value":"RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1."}],"affected":[{"vendor":"rabbitmq","product":"rabbitmq-server","versions":[{"version":">= 4.2.0, < 4.2.7","status":"affected"},{"version":">= 4.3.0, < 4.3.1","status":"affected"}]}],"references":[{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf","name":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-hwqx-2gfg-89qf","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7","name":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7","tags":["x_refsource_MISC"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1","name":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-23T20:12:00.076Z"},"source":{"advisory":"GHSA-hwqx-2gfg-89qf","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-24T14:11:25.836720Z","id":"CVE-2026-66067","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-24T14:11:44.566Z"}}]}}}