{"id":"CVE-2026-67240","title":"RabbitMQ is a messaging and streaming broker","summary":"RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, pattern_to_regex maps % -> .*? and _ -> ., then compiles ^...$ with only [unicode]; re:run is called with only [{capture, none}] - no explicit match_limit. …","severity":"low","cvss":2.3,"cvssVector":"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","cwe":["CWE-1333"],"vendor":"rabbitmq","product":"rabbitmq-server","affected":["rabbitmq-server >= 4.2.0, < 4.2.7","rabbitmq-server >= 4.3.0, < 4.3.1"],"published":"2026-09-23","updated":"2026-09-24","sourceUpdated":"2026-09-24T15:17:29.910","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-67240","references":[{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7","label":"security-advisories@github.com"},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1","label":"security-advisories@github.com"},{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-59c5-553c-57m2","label":"security-advisories@github.com"},{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-59c5-553c-57m2","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67240.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-67240"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2539764"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-67240"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67240"},{"url":"https://access.redhat.com/errata/RHSA-2026:67552"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","score-dispute"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-24T14:24:20.497820Z"},"cvssSource":"cna","scores":{"cna":2.3,"vendor":6.5},"ingestedAt":"2026-09-23T20:32:10.758Z","patched":["hardened_images"],"epss":0.00259,"epssPercentile":0.15749,"slug":"CVE-2026-67240","body":"## Overview\n\nRabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, pattern_to_regex maps % -> .*? and _ -> ., 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Hardened Images · no fix planned: Red Hat Hardened Images · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67240.json)\n- **RHSA-2026:67552** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67552)","depth":"twilight","depthScore":25,"depthScoreParts":{"impact":12.6,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":210203,"id":"CVE-2026-67240","ts":1790264802220,"field":"exploit_available","old":"false","new":"true"}]}