{"id":"DEBIAN-CVE-2026-66071","details":"RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1, Atom exhaustion: OAuth2 JWT tag: scope values. extractscopes/1 parses scopes of the form .tag: and calls rabbitdatacoercion:toatom() to convert to a tag atom. The token signature is verified first, so the attacker cannot forge scopes , but in IdP configurations where scope content is user-influenced, each login with a novel tag value leaks one In deployments where users can influence the scopes included in their IdP-issued JWT rabbitmqauthbackendoauth2 enabled IdP permits attacker-influenced scope values in signed tokens. This issue is fixed in versions 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1.","modified":"2026-09-26T12:00:08.344573782Z","published":"2026-09-25T17:17:09.987Z","upstream":["CVE-2026-66071"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-66071"}],"affected":[{"package":{"name":"rabbitmq-server","ecosystem":"Debian:12","purl":"pkg:deb/debian/rabbitmq-server?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10.8-1.1","3.10.8-1.1+deb12u1","3.10.8-2","3.10.8-3","3.10.8-4","3.12.1-1","3.12.1-1.1","4.0.5-1","4.0.5-10","4.0.5-11","4.0.5-12","4.0.5-13","4.0.5-14","4.0.5-2","4.0.5-3","4.0.5-4","4.0.5-5","4.0.5-6","4.0.5-8","4.0.5-9","4.3.0-1","4.3.0-2","4.3.0-3","4.3.2-1","4.3.2-2","4.3.2-3","4.3.2-4","4.3.2-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66071.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Debian:13","purl":"pkg:deb/debian/rabbitmq-server?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.5-10","4.0.5-11","4.0.5-12","4.0.5-13","4.0.5-14","4.0.5-6","4.0.5-6+deb13u1","4.0.5-6+deb13u2","4.0.5-8","4.0.5-9","4.3.0-1","4.3.0-2","4.3.0-3","4.3.2-1","4.3.2-2","4.3.2-3","4.3.2-4","4.3.2-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66071.json"}},{"package":{"name":"rabbitmq-server","ecosystem":"Debian:14","purl":"pkg:deb/debian/rabbitmq-server?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.3.2-1"}]}],"versions":["4.0.5-10","4.0.5-11","4.0.5-12","4.0.5-13","4.0.5-14","4.0.5-6","4.0.5-8","4.0.5-9","4.3.0-1","4.3.0-2","4.3.0-3"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-66071.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:H/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"}]}