{"id":"UBUNTU-CVE-2026-67240","details":"RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, pattern_to_regex maps % -\u003e .*? and _ -\u003e ., then compiles ^...$ with only [unicode]; re:run is called with only [{capture, none}] - no explicit match_limit. A pattern like %_%_..._%X becomes ^.*?..*?.....*?.X$ with overlapping lazy quantifiers. The whole-expression cap is ?MAX_EXPRESSION_LENGTH=4096 chars / ?MAX_TOKENS=200; a LIKE string literal is one token, so ~2000 %_ pairs fit. SQL filters are accepted unconditionally at rabbit_amqp_session.erl:3264 (no feature flag). Evaluated per-message at rabbit_stream_queue.erl:1439. OTP's default 10M match_limit caps each match at ~100-200 ms (not seconds), and the re NIF yields to the scheduler. An authenticated AMQP 1.0 consumer with read+write on a stream queue can cause ~100-200 ms of CPU per delivered message via a crafted LIKE filter, multiplied across thousands of messages and parallel sessions - a substantial backtracking-driven CPU amplification. Preconditions include AMQP 1.0 with stream queues in use Attacker can attach a receiver with a filter (read permission) and publish messages with long property values (write permission). This issue is fixed in versions 4.2.7 and 4.3.1.","modified":"2026-09-25T06:36:38.856411312Z","published":"2026-09-24T00:00:00Z","upstream":["CVE-2026-67240"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-67240"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-67240"},{"type":"REPORT","url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-59c5-553c-57m2"},{"type":"REPORT","url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7"},{"type":"REPORT","url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1"}],"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-2026-67240.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_version":"3.6.10-1ubuntu0.5","binary_name":"rabbitmq-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67240.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-2026-67240.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_name":"rabbitmq-server","binary_version":"3.9.27-0ubuntu0.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67240.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-2026-67240.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_name":"rabbitmq-server","binary_version":"4.0.5-10ubuntu5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67240.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}