CVE-2026-67227

RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7 and 4.3.1, Atom exhaustion: toatom on global-parameter :name. resourceexists/2 (and the PUT/DELETE handlers) call rabbitdatacoercion:toatom/1 on the :name URL path segment. toatom/1 uses binarytoatom/2 (unsafe). The endpoint requires policymaker (not management, but below A user with the policymaker tag can crash the node by exhausting the atom table via repeated requests to /api/global-parameters/:name with unique :name Management plugin enabled policymaker tag ~1M HTTP. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7 and 4.3.1.

• https://github.com/rabbitmq/rabbitmq-server/commit/8fbe6d8112427e85fb9a9206b3eb6e9a3ddd3e39
• https://github.com/rabbitmq/rabbitmq-server/commit/fc591e7ee27a29657ca960930acefd3e4217e007
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q7x8-97rh-cr24