CVE-2026-66078

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15 and 4.0.20 and 4.1.11 and 4.2.6, protected tag bypass via bulk-delete. dELETE /api/users/:name refuses to delete users tagged protected (rabbitmgmtwmuser:deleteresource/2 checks isprotecteduser). POST /api/users/bulk-delete iterates the supplied username list and calls rabbitauthbackendinternal:deleteuser/2 directly , that function has no protected-tag check , so the guard is silently An administrator can delete protected-tagged service accounts via the bulk endpoint, bypassing a safeguard the test suite confirms is rabbitmqmanagement enabled Attacker has the administrator tag A protected-tagged user. This issue is fixed in versions 3.13.15 and 4.0.20 and 4.1.11 and 4.2.6.

• https://github.com/rabbitmq/rabbitmq-server/commit/e5b890a64b42ec1f79a8e9d735512150cf77479cPatch
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6Release Notes
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-j9m2-hw6x-rqr9Exploit
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-j9m2-hw6x-rqr9Exploit