{"id":"UBUNTU-CVE-2026-44838","details":"RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization. This vulnerability is fixed in 4.2.4 and 4.3.0.","modified":"2026-06-04T22:56:02.268028082Z","published":"2026-05-27T15:16:00Z","withdrawn":"2026-06-04T20:32:00Z","upstream":["CVE-2026-44838"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-44838"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-44838"},{"type":"REPORT","url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8v"}],"affected":[{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.5.4-1","3.5.4-3","3.5.4-3.1","3.5.7-1","3.5.7-1ubuntu0.16.04.1","3.5.7-1ubuntu0.16.04.2","3.5.7-1ubuntu0.16.04.4","3.5.7-1ubuntu0.16.04.4+esm1","3.5.7-1ubuntu0.16.04.4+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"rabbitmq-server","binary_version":"3.5.7-1ubuntu0.16.04.4+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.6.10-1","3.6.10-1ubuntu0.1","3.6.10-1ubuntu0.3","3.6.10-1ubuntu0.4","3.6.10-1ubuntu0.5"],"ecosystem_specific":{"binaries":[{"binary_name":"rabbitmq-server","binary_version":"3.6.10-1ubuntu0.5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.7.8-4ubuntu2","3.7.18-1","3.8.2-0ubuntu1","3.8.2-0ubuntu1.1","3.8.2-0ubuntu1.2","3.8.2-0ubuntu1.3","3.8.2-0ubuntu1.4","3.8.2-0ubuntu1.5","3.8.3-0ubuntu0.1","3.8.3-0ubuntu0.2","3.8.3-0ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_name":"rabbitmq-server","binary_version":"3.8.3-0ubuntu0.3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.8.9-3ubuntu1","3.9.8-1","3.9.8-2","3.9.8-3","3.9.8-5","3.9.8-6","3.9.13-1","3.9.13-1ubuntu0.22.04.1","3.9.13-1ubuntu0.22.04.2","3.9.27-0ubuntu0.1","3.9.27-0ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_version":"3.9.27-0ubuntu0.2","binary_name":"rabbitmq-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.12.1-1","3.12.1-1ubuntu1","3.12.1-1ubuntu1.2","3.12.1-1ubuntu1.4"],"ecosystem_specific":{"binaries":[{"binary_version":"3.12.1-1ubuntu1.4","binary_name":"rabbitmq-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.5-2ubuntu2","4.0.5-6ubuntu1","4.0.5-8ubuntu1","4.0.5-8ubuntu2","4.0.5-8ubuntu2.1"],"ecosystem_specific":{"binaries":[{"binary_name":"rabbitmq-server","binary_version":"4.0.5-8ubuntu2.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.5-8ubuntu2","4.0.5-10ubuntu1","4.0.5-10ubuntu2","4.0.5-10ubuntu3","4.0.5-10ubuntu4","4.0.5-10ubuntu5"],"ecosystem_specific":{"binaries":[{"binary_version":"4.0.5-10ubuntu5","binary_name":"rabbitmq-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44838.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:N"},{"type":"Ubuntu","score":"medium"}]}