{"schemaVersion":3,"id":"CVE-2026-67420","aliases":["UBUNTU-CVE-2026-67420","DEBIAN-CVE-2026-67420"],"status":"published","duplicateOf":null,"title":null,"description":"RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, RabbitMQ OAuth credential refresh retains revoked runtime tags. when an existing AMQP connection refreshes from an OAuth token that grants the impersonator tag to a valid same-username token that no longer grants that tag, RabbitMQ updates the OAuth backend implementation (token/scopes/expiry) but leaves the connection's runtime #user.tags unchanged. rabbitaccesscontrol:checkuserid/2 then still honors the stale impersonator tag, so the connection (including newly opened channels) can continue publishing messages with a foreign AMQP userid after that privilege should have been revoked. A fresh connection using the downgraded token correctly refuses the same publish, proving the defect is stale session state rather than the token Limited to connections that once held impersonator and successfully refresh to a downgraded same-username rabbitauthbackendoauth2 (or an equivalent refresh-capable backend that returns tags) is enabled for This issue is fixed in versions 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5.","dates":{"published":"2026-09-25T16:42:49.000Z","modified":"2026-09-29T19:32:12.337Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.5,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":2.3,"severity":"low","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Ubuntu","score":2.3,"severity":"low","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","exploitability":null,"impact":null,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Debian","score":2.3,"severity":"low","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":2.3,"severity":"low","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":6.5,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00234,"percentile":0.13384,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-09-26T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00234,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00234,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00234,"percentile":0.13384}],"last30":[{"date":"2026-09-26T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00238,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00234,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00234,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00234,"percentile":0.13384}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"GITHUB_RABBITMQ_RABBITMQ-SERVER","name":"Rabbitmq Server","source":"github","url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-gh3x-4x42-fvq8","maturity":"poc","reliabilityScore":0.3,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":1,"weaknesses":[{"id":"CWE-862","name":"Missing Authorization","description":"The product does not perform an authorization check when an actor attempts to access a resource or perform an action.","type":"weakness","status":"Incomplete","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/862.html"}],"affected":[{"vendor":"broadcom","product":"rabbitmq_server","name":"rabbitmq server","label":"rabbitmq_server","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 3.13.0, < 3.13.19","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.0.0, < 4.0.24","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.1.0, < 4.1.15","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.2.0, < 4.2.10","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.3.0, < 4.3.5","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 3.13.0, < 3.13.19 | ≥ 4.0.0, < 4.0.24 | ≥ 4.1.0, < 4.1.15 | ≥ 4.2.0, < 4.2.10 | ≥ 4.3.0, < 4.3.5","eol":null,"hubHref":"/vendor/broadcom/rabbitmq_server"},{"vendor":"debian","product":"rabbitmq-server","name":"rabbitmq-server","label":"rabbitmq-server","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/rabbitmq-server","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 4.3.6-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 4.3.6-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"rabbitmq-server","name":"rabbitmq-server","label":"rabbitmq-server","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/rabbitmq-server","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"rabbitmq","product":"rabbitmq-server","name":"rabbitmq-server","label":"rabbitmq-server","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 3.13.0, < 3.13.19","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.0.0, < 4.0.24","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.1.0, < 4.1.15","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.2.0, < 4.2.10","noFixRecorded":false,"fixedIn":null},{"text":"≥ 4.3.0, < 4.3.5","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 3.13.0, < 3.13.19 | ≥ 4.0.0, < 4.0.24 | ≥ 4.1.0, < 4.1.15 | ≥ 4.2.0, < 4.2.10 | ≥ 4.3.0, < 4.3.5","eol":null,"hubHref":"/vendor/rabbitmq/rabbitmq-server"}],"affectedCount":4,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-86fm-44m9-rqjx","label":"github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-86fm-44m9-rqjx","hostname":"github.com","tags":["X Refsource CONFIRM","REPORT","Vendor Advisory","Mitigation","Exploit"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/commit/5de287d213765ca592ff5848ad2f6b9b98ee6772","label":"github.com/rabbitmq/rabbitmq-server/commit/5de287d213765ca592ff5848ad2f6b9b98ee6772","hostname":"github.com","tags":["X Refsource MISC","REPORT","Patch"]},{"url":"https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5","label":"github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5","hostname":"github.com","tags":["X Refsource MISC","REPORT","Release Notes"]},{"url":"https://ubuntu.com/security/CVE-2026-67420","label":"ubuntu.com/security/CVE-2026-67420","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-67420","label":"www.cve.org/CVERecord?id=CVE-2026-67420","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-67420","label":"security-tracker.debian.org/tracker/CVE-2026-67420","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["RHSA-2026:67552"],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-09-25T16:42:49.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-29T19:32:12.337Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":36,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T05:03:11.330Z","stale":false,"partial":false}}